Advertisement

Courses

UK Full Permaculture Design and Introduction to Permaculture Courses are listed FREE in Permaculture and on this page for approximately 3 months. Overseas Permaculture Courses and Special Courses listings cost £20 (£24 inc. VAT) per entry.

Permaculture.co.uk receives receives 3 million page views per year and reaches more than 280,000 people through its social media.

To Advertise a Course

Contact us 3, 6 or even 9 months before your course takes place, to ensure it appears. The pages inside the print version of Permaculture magazine are of course limited but we do aim to share the coverage around. Contact Tony on 01730 823 311 or [email protected]

Permaculture Teachers

Did you know we offer each of your new UK permaculture students a FREE recent back issue of Permaculture (all we ask is that you support us with covering the postage cost), 30% OFF all books published by Permanent Publications and 10% OFF other books, tools and products from www.permaculture.co.uk/shop? Contact Tony on 01730 823 311 or [email protected] 

Catagories are:

 

Full Permaculture Design


ARGENTINA
Venue:    14IPC venue, Misiones
Dates:    12 - 25 November 2021, TBC
Led by:    Beatriz Ramirez and guests
Web:    https://tinyurl.com/5aj4c367

ARGENTINA
Children, Youth & all courses TBC
Venue:     14IPC venue, Misiones
Dates:     November 2021, TBC
Led by: Sophia & Itiba Martínez Ramirez
Web:     https://tinyurl.com/5aj4c367

AUSTRALIA
Venue:    Crystal Waters EcoVillage
Dates:    8 - 22  August 2021
Led by:    Robin Clayfield & the Crystal Waters Community Cooperative
Phone:    +61 754 944 707
Web:    https://crystalwaters.org.au/permaculture-design-course/

AUSTRALIA
Venue:    Online
Dates:    Various throughout 2021
Led by:    David Holmgren, Nick Ritar & Kirsten Bradley
Phone:    +61 253 004 473
Web:    www.milkwood.net/courses

AUSTRALIA & WORLDWIDE
Venue:    Zaytuna Farm, NSW, Australia, Florida USA and others
Dates:    Various 2021
Led by:    Geoff Lawton
Phone:    +61 (0)416 119 965
Web:    https://zaytunafarm.com/courses-events

DENMARK
Venue:    Hoerhaven, Fuglebjerg
Dates:    12 - 26 June 2021
Led by:    Aranya & guests
Phone:    01503 240946
Web:    www.learnpermaculture.com/courses/courses/hoerhaven-pdc

ENGLAND, CORNWALL
Venue:    Trelowia, East Looe
Dates:    21 August - 4 September 2021
Led by:    Aranya
Phone:    01503 240 946
Web:    www.learnpermaculture.com/courses/courses/trelowia-pdc

ENGLAND, DEVON
Venue:    The Apricot Centre, Totnes
Dates:    September 2021 - February 2022, 6 weekends
Led by:    Marina O’Connell, Bob Mehew
Phone:    07540 445 851
Web:    www.apricotcentre.co.uk/training-courses

ENGLAND, DORSET
Venue:    High Heathercombe Centre
Dates:    6 - 20 November 2021
Led by:    Aranya, Klaudia van Gool
Phone:    01503 240 946
Web:    www.learnpermaculture.com/courses/courses/heathercombe-pdc-spring

ENGLAND, DORSET
Venue:    Ourganics Evolving Systems, Litton Cheney, Dorchester
Dates:    24 July - 7 August 2021
Led by:    Aranya, Pat Bowcock
Phone:    01503 240 946
Email:    [email protected]
Web:    www.learnpermaculture.com/courses/courses/ourganics-summer-pdc

ENGLAND, DORSET
Venue:    High Heathercombe Centre
Dates:    6 November - 21 November 2021
Led by:    Aranya, Klaudia van Gool
Phone:    01503 240 946
Web:    http://www.learnpermaculture.com/courses/courses/heathercombe-pdc-autumn

ENGLAND, DURHAM
Venue:    Alington House, Abundant Earth
Dates:    2021, weekends
Led by:    Wilf Richards
Phone:    07906 439 084
Email:    [email protected]

ENGLAND, EAST SUSSEX
Mainly online, but with some site visits
Venue:    Brighton & Sussex locations
Dates:    Various 2021,
Led by:    Brighton Permaculture Team
Web:    https://tinyurl.com/y5rfutug

ENGLAND, GLOUCESTERSHIRE
Venue:    Common Edge, Stroud (including some field visits)
Dates:    April - July 2021
Led by:    Helen Pitel, Emily Howgate
Web:    https://tinyurl.com/y37xt7rf

ENGLAND, HEREFORDSHIRE
Venue:    Applewood Permaculture Centre
Dates:    Various 2021, weekends
Led by:    Chris Evans, Tomas Remiarz
Phone:    07786 262 864
Web:    www.applewoodcourses.com

ENGLAND, KENT
Venue: East Kent Permaculture learning network
Dates: March - July 2022
Led by Jo Barker, Helen Smith
Phone 07747 386 994
Web: www.dynamic.equilibrium.co.uk

ENGLAND, LANCASHIRE
Venue:    Manchester Road Community Arts Centre, Bury
Dates:    2021 - 2022, various weekends
Led by:    Angus Soutar
Web:    https://northernschool.info/bury

ENGLAND, LONDON
Venue:    Furtherfield Commons, Harringay
Dates:    Various 2021
Led by:    Graham Burnett & guests
Web:    https://spiralseed.co.uk/product/design-4-action

ENGLAND, OXFORDSHIRE
Venue:    Oxford, various locations
Dates:    Various dates in 2021
Led by:    Rachel Hammond
Web:    www.facebook.com/incredibleedibleoxford/

ENGLAND, SOMERSET
Vegan Permaculture Design Course
Venue:    Brook End LAND Centre,         
Dates:    8 - 12 August 2021
Led by:    Graham Burnett, Nicole Vosper
Web:    https://spiralseed.co.uk/vegan-permaculture/

ENGLAND, WEST YORKSHIRE
Venue:    Hollybush Conservation Centre,
Dates:    Various 2021
Led by:    Leeds Permaculture
Web:    www.leedspermaculturenetwork.org/courses.html

FRANCE
Venue:    Afrinoon Permaculture,  Bellevue
Dates:    4 - 18 June 2021
Led by:    Karen Noon
Phone:    +33 788 113 505
Web:    www.afrinoonpermaculture.org/

GREECE
Venue:    Tinos Ecolodge, Tinos Island
Dates:    27th September - 10th October 2021
Led by:    Peter Cow and guests
Phone:    +30 6 974 467 611
Email:     [email protected]
Web:   http://www.tinosecolodge.gr/eco-lodge-activities/

IRELAND
Venue: Carraig Dulra, Co. Wicklow.
Dates: May 2021 and June 2021 (2 PDC'S)
Led by: Hannah Mole, Suzie Cahn & guests.
Phone: +353 851 969 790
Email: [email protected]
Web: www.dulra.org/courses


ITALY
Venue:    Calabria
Dates:    28 August - 9 September 2021
Led by:    Eduardo Terzidis
Web:    www.eduardoterzidis.com/pdc-italy

NEW ZEALAND
Venue:    Golden Bay, South Island
Dates:    Various 2021, dates TBA
Led by:    Robina McCurdy & guests
Web:    www.gbslc.org/sustainable-living-course

NEW ZEALAND
Venue:    The Waihōanga River Lodge & Retreat, on the Kapiti coast
Dates:    Various 2021
Led by:    Gary & Emily Williams & guests
Web:    https://tinyurl.com/yyljmo7q

PORTUGAL
Venue:    S. Miguel Island, Azores
Dates:    May - June 2021
Led by:    Helder Valente    
Web:    www.newschoolpermaculture.courses/2020/12/pdc-permaculture-design-course...

PORTUGAL
Venue:    Aldeia do Vale Projecto Agroecológico
Dates:    1 - 14 June 2021
    18 - 31 July 2021
Led by:    Sílvia Floresta, Orlando Pereira
Phone:    +351 963 500 112
Web:    www.aldeiadovale.com

PORTUGAL
Venue:    Terra Alta, Permaculture Education & Research Centre
Dates:    13 - 26 June 2021
    4 - 17 July 2021
    25 July - 7 August 2021
Led by:    Pedro Valdjiu & guests
Web:    https://tinyurl.com/yar97de8

SCOTLAND
Venue:    Garden Cottage, Berwickshire
Dates:    Various 2021 TBA
Led by:    Graham Bell, Nancy Woodhead
Phone:    01890 882 448
Web:    http://grahambell.org

SCOTLAND
Venue:    The Concrete Garden, Glasgow
Dates:    2021, various weekends     
Led by:    Lusi Alderslowe, Ed Tyler, Paula McCabe & guests
Phone:    07787 376 475
Web:    https://lusialderslowe.wordpress.com/glasgow-pdc

SCOTLAND
Venue:    Findhorn Ecovillage
Dates:    28 August - 10 September 2021
Led by:    Findhorn College
Phone:    07771 743 861
Web:    www.findhorncollege.org

SPAIN
Venue:    Can Lliure, Sales de Llierca
Dates:    11 - 25 June 2021
Led by:    Martin Bastide, Roman Eisenkölbl
Email:    [email protected]
Web:    http://www.soilsunsoul.net

SPAIN
Venue:    Supernatural Permaculture Centre, Sierra Nevada Mountains
Dates:    25 September - 10 October 2021
    13 - 28 November 2021
Led by:    Cathy Whitefield & guests
Phone:    +34 858 995 872
Web:    www.supernatural-permaculture.com

SPAIN
Venue:    Sunseed Desert Technology
Dates:    2021 dates to be announced
Led by:    Liselotte Willemijn
Phone:    +34 950 525 770
Web:     http://circlepermaculture.com/#

USA, CALIFORNIA
Venue:    Sivananda Ashram Yoga Farm,
Dates:     Various 2021
Led by:    Spencer Nielsen, Lydia Neilsen
Phone:    +1 5 302 729 322
Web:    yogafarm.org/pdc

USA, COLORADO
Venue:    Sunrise Ranch, Loveland CO
Dates:     12 -24 August 2021
Led by:    Tara Rea, Patrick Padden, Avery Ellis
Phone:    +1 9 709 994 306
Web:    boulderpdc.com

USA, MISSOURI
Venue:    EarthDance Organic Farm School, Ferguson, MO
Dates:     Various 2021, TBA
Led by:    Jason Gerhardt, Pandora Thomas & guests
Web:    https://earthdancefarms.org/farmers/classes    

USA, NORTH CAROLINA
Permaculture Apprenticeship
Venue:     Wild Abundance, Weaverville Asheville
Dates:    Various 2021, TBA
Led by:    Luke Cannon, Tyler Lavenburg
Web:    www.wildabundance.net/classes/earthskills-and-permaculture/

USA, WESTERN MASSACHUSETTS
Venue:    Sowing Solutions Permaculture Design & Education at The Mill in Shelburne Falls
Dates:    2021 TBC, weekends
Led by:    Kay Cafasso,Keith Zaltzberg, Llani Davidson, Walker Korby, Dave Dion and guests
Web:    www.permacultureseries.org/about-the-permaculture-design-course-pdc.html

WALES
Venue:    Various locations
Dates:    August - October 2021, three weekends
Led by:    Angie Polkey, Alice Gray & guests
Email:    [email protected]

Introduction to Permaculture

AUSTRALIA
Venue:    Zaytuna Farm, NSW
Dates:    Various 2021
Led by:    Geoff Lawton
Phone:    +61 416 119 965
Web:    https://zaytunafarm.com/courses-events

AUSTRALIA
Venue:    Permaculture Pathways, Eudlo
Dates:    Various 2021
Led by:    Sonya Wallace and guests
Phone:    +61 2 53 004 473
Email:    [email protected]

ENGLAND, DEVON
Venue:    The Apricot Centre, Totnes
Dates:    11 - 12 September 2021
Led by:    Marina OC
Phone:    07540 445 851
Web:    www.apricotcentre.co.uk

ENGLAND, EAST AND WEST SUSSEX
Venue:     Stanmer Park, various venues
Dates:    Various dates 2021
Led by:    Brighton Permaculture Trust
Phone:    01342 850 815
Web:    https://brightonpermaculture.org.uk/events/event/introduction-to-permacu...

ENGLAND, HAMPSHIRE
Venue:    Sustainability Centre, Hampshire
Dates:    7 - 10 October 2021
Led by: Aranya
Phone:    01730 823 166
Web:    https://www.sustainability-centre.org/courses.html

ENGLAND, KENT
Venue: Physic Community Garden, Faversham
Dates: September 2021
Led by Jo barker, Helen Smith
Phone 07747 386 994
Web: www.dynamic.equilibrium.co.uk

ENGLAND, OXFORDSHIRE
Venue: Braziers Park
Date:   24 - 25 July 2021
18 - 19 September 2021
Led by: Trish Whitham, Phil  Pritchard
Phone: 07974 916 954
Web: www.braziers.org.uk/programme

ENGLAND, OXFORDSHIRE
Venue: FarmEd Centre, Chipping Norton
Dates: Anytime
Email: [email protected]
Web: www.farm-ed.co.uk



FRANCE
Venue:    La Brande Woodland, Poitiers
Dates:     Various 2021
Led by:    Various
Email:    [email protected]

NEW ZEALAND
Venue:    Kahikatea Farm, Wellington
Dates:    4 days, Friday-Monday
Led by:    The Kahikatea Farm Team
Phone:    +21 02 223 582
Web:    https://kahikateafarm.co.nz/product/4-day-introduction-to-permaculture-d...

USA, OREGON
Free Course. Material currently online
Venue:    Oregon State Ecampus, Corvallis
Dates:    Various 2021
Led by:    Andrew Millison
Web:    https://open.oregonstate.edu/courses/permaculture/

WALES
Check with them for up-to-date details
Venue:    Pembrokeshire, TBC
Dates:    7 - 9 August 2021
Led by:    Angie Polkey
Email:    [email protected]

WORLDWIDE
Venue:    Online
Dates:    Various throughout 2021/2022
Led by:    David Holmgren, Nick Ritar, Kirsten Bradley
Phone:    +61 253 004 473
Web:    www.milkwood.net/courses

WORLDWIDE
Venue: Online
Dates: Various throughout 2021/2022
Led by: David Holmgren, Nick Ritar, Kirsten Bradley
Phone: +61 253 004 473
Web: www.milkwood.net/courses

Special Courses

ACTIVATING CULTURAL EMERGENCE (ACE) 2021
Venue:    Applewood Permaculture Centre
Dates:    Spring 2021, TBA
Led by:    Looby Macnamara
Web:    https://applewoodcourses.com/uk_courses/activating-cultural-emergence-ac...

AGROECOLOGY LAND TRUST
Mushroom Cultivation, Off Grid Solar, Carpentry, Natural Building,
Green Roofing and Soil Carbon
Venue:    Coed Talylan, Wales
Led by:    Coed Talylan
Phone:    07808 168 562
Web:    www.agroecology.co.uk

BEN LAW OPEN DAYS
Ben’s courses go ahead with all due testing
Venue:    Ben’s woodland, West Sussex
Dates:    Various 2021
Led by:    Ben Law
Phone:    07966 193 154
Web:    www.ben-law.co.uk

BRIGHTON PERMACULTURE TRUST
The Trust is constantly reviewing the COVID-19 situation to deliver safe learning. Outside courses are going ahead, with smaller numbers and social distancing.
Venue:    Stanmer Park & various sites
Dates:    Various 2021
Led by:    Brighton Permaculture Trust team
Web:    https://brightonpermaculture.org.uk/events/event/brighton-permaculture-t...

CARBON AMBASSADORS
Online
Dates: 28 May 2021 to 9th July 2021
Led by: Mukti Mitchell, Satish Kumar, Penney Poyzer, Peter Owen Jones
 and other guest speakers
Web: https://carbonsavvy.uk/event/carbon-ambassadors-course-2/
In response to the accelerating threat of global environmental catastrophe, low carbon living expert Mukti Mitchell has joined up with leading green thinkers to present the landmark new Carbon Ambassadors course, sharing simple tools everyone can use to reduce their carbon footprint and improve their quality of life. Wwill teach how to reduce emissions in all key areas of life, including food, shopping, transport, heating your home, and holidays and travel. “While many of us look to the world’s governments to sort out the problem, almost all CO2 emissions are actually produced by the products and services bought by us as individuals, so it’s up to each one of us to play our part. Many people fear that making the necessary lifestyle changes will cost too much and reduce their quality of life, when actually the opposite is true. Our new Carbon Ambassadors course will give people the knowledge and tools to not only cut their carbon footprint, but also to lead happier, healthier lives and save money in the process.”

CULTURAL EMERGENCE EFFECTIVE DESIGN (CEED) 2021
Venue:    Applewood Permaculture Centre
Dates:    Spring 2021, TBA
Led by:    Looby Macnamara, Andy Goldring
Web:    https://applewoodcourses.com/uk_courses/cultural-emergence-effective-des...

DESIGN YOUR OWN FORAGER’S GARDEN
Venue: Small Farm, Fairlight, East Sussex
Dates: 11 September 2021
Led by: Anna Locke
Phone: 07946 228 110
Web: https://www.annalockepermaculture.co.uk/



FOREST GARDENING / FOOD FORESTS
Venue:    Dartington, Devon
Dates:    Various 2021
Led by:    Martin Crawford
Web:    www.agroforestry.co.uk

GROWING NO DIG
Venue:    Homeacres, Somerset
Dates:    Various 2021
Led by:    Charles Dowding
Web:    www.charlesdowding.co.uk

The Incredible Edible Garden
Venue:    Online
Dates:    Start anytime
Led by:    Morag Gamble
Web:    https://ourpermaculturelife.com/the-incredible-edible-garden/

International Forest Garden / Food Forest Symposium
Venue:    Dartington Hall, Devon, UK
Dates:    31 May - 4 June 2021
Led by:    Martin Crawford
Web:    https://www.agroforestry.co.uk/symposium/

INTRODUCTION TO AGROFORESTRY AND DESIGN
Venue:    The Apricot Centre, Devon
Dates:    24 - 26 September 2021
Led by:    Marina O’Connell
Web:    www.apricotcentre.co.uk/training-courses

INTRODUCTION TO FOREST GARDENING / FOOD FORESTS
England, Kent
Venue: Physic Community Garden, Faversham
Dates: 9 October 2021
Led by Jo Barker, Helen Smith
Phone 07747 386 994
Web: www.dynamic.equilibrium.co.uk

I’VE BOUGHT A WOODLAND
WHAT DO I DO NOW?
Venue:    Ben Law’s West Sussex woodland
Dates:    Various 2021
Led by:    Ben Law
Web:    www.ben-law.co.uk

MUSHROOM CULTIVATION
Venue:    Coed Talylan, Brecon Beacons
Dates:    Ongoing
Led by:    James Skrivez
Web:    www.agroecology.co.uk

MUSHROOM CULTIVATION
Venue:    Online
Dates:    Various throughout 2021/2022
Led by:    Nick Ritar, Kirsten Bradley
Phone:    +61 253 004 473
Web:    https://courses.milkwood.net/mushroomcultivation

NO DIG GARDEN
Workshops/virtual talks on seasonal plant-based recipes, organic no dig gardening, homegrown potions, edible garden design, permaculture, small-scale homesteading, living lightly & abundantly
Venue:    Various to suit
Dates:    Various 2021
Led by:    Stephanie Hafferty
Web:    https://nodighome.com/

ORGANIC / BIODYNAMIC GARDENING & FARMING
Venue:    BioDynamic Agricultural College. Work based & Distance Learning
Dates:    Online or full time two year work based apprentice style learning
Led by:    BDA tutors
Phone:    07786 262 864
Web:    www.bdacollege.org.uk

Permaculture Educators Program
Permaculture Design Certificate & Permaculture Teacher Certificate
Venue:    Online
Dates:    Start anytime
Led by:    Morag Gamble
Phone:    +61 400 336 413
Web:    https://permacultureeducationinstitute.org

PERMACULTURE KIDS
Online
Aimed at 8 to 12 year olds and delivered live via zoom.
Games, hands on challenges and open discussion. Includes a physical resource box sent through the post. Students explore the ethics of earth care, people care and fair shares for all species plus permaculture design methods and their application. Studying ecosystems and social systems and where they can fit in to it all and create beneficial change.
Dates: Five weeks starting 17th June 2021
Five weeks starting 18th June 2021



Permaculture Living
Dates:    Various throughout 2021/2022
Led by:    David Holmgren, Nick Ritar, Kirsten Bradley
Web:    https://courses.milkwood.net/permacultureliving

PRACTICAL SUSTAINABILITY
Check their website for up-to-date details, online options have been running
Venue:    Shift Bristol
Dates:    Typically 2.5 days per week
Led By:    Sarah Pugh and various Shift Bristol tutors
Web:    www.shiftbristol.org.uk

REWILDING CAMPS
Venue:    Embercombe and Ecosystem  Restoration Camps, Devon
Dates:    1 - 6 July 2021
        23 - 28 September 2021
        27 January - 1 February 2022
Led by:    The EmbercombeTeam
Web:    embercombe.org/rewilding-camps

ROUNDWOOD TIMBER FRAMING
Check Ben’s website for up-to-date details
Venue:    Ben Law’s West Sussex woodland
Dates:    Various 2021/2022, 5 days
Led by:    Ben Law
Phone:    07966 193 154
Web:    www.ben-law.co.uk

SELF-BUILDING AN EARTHSHIP IN EUROPE VIRTUAL COURSE
Self-building an Earthship online course comprises 7 modules, each of which is a week-long.
Venue:    Online
Dates:    Various 2021/2022
Led by:    Brighton Permaculture Trust
Web:    https://brightonpermaculture.org.uk/events/event/self-building-an-earths...

VEGAN PERMACULTURE
Plus online
Venue:    Essex, London and others
Dates:    Various 2021
Led by:    Graham Burnett
Web:    www.spiralseed.co.uk

ONLINE COURSES

PM subscriber offer, use code:
PERMACULTUREUK
Led by:    Noosa Forest Retreat
Web:    www.permaculturecourseonline.com/enrolment/?plan=1803

AUSTRALIA
Venue:   Online
Dates:    Various throughout 2021
Led by:    David Holmgren, Nick Ritar and Kirsten Bradley
Phone:     (00 61) 2 5300 4473
Web:    www.milkwood.net/courses


Led by:    Various
Web:    www.PermacultureVisions.com


Led by:    Scott Pittman, Durga
Web:    http://organiclifeguru.com/course/permaculture-design-course


Led by:    Stefania Strega Scoz
Web:    www.integralpermaculture.org


Led by:    Simon Inglis
Web:    www.kultcha.org


Led by:    Matt Powers & guests
Web:    https://tinyurl.com/mattpowersAPSO


Led by:     Andrew Millison
Web:    https://open.oregonstate.edu/courses/permaculture


Led by:    Heather Jo Flores
Web:    www.permaculturewomen.com/permaculturedesigncourse


Led by:    Angus Soutar
Web:    https://northernschool.info/permaculture-design-course-online


Led by:    Aldeia do Vale Project, Portugal
Web:    https://tinyurl.com/y4mjh3jk


Led by:    Joshua Gomez
Web:    www.permaculturekernow.org


Led by:    Caroline Aitken with guest tutors
Web:    http://patrickwhitefield.co.uk


Led by:    Dr. Alan Enzo, Jessica Enzo, Dr. Philipp Schuster, Steve Hart, Steve Cran
Web:    permacultureeducation.com


Led by:    Douglas Barnes
Web:    https://tinyurl.com/yhdttbzv

Led by: Permaculture Association Britain
Web:    permaculture.org.uk/permaculture-course


Web:    https://freepermaculture.com/


Web:    https://www.permaculture.org.uk/diploma


Venue: Aldeia do Vale Projecto Agroecológico
Dates: 15th to 28 May 2021
Led by: Sílvia Floresta & Orlando Pereira
Phone: +351 963500112
Email: [email protected]
Web:www.aldeiadovale.com

PERMACULTURE LIVING
Dates: Various throughout 2021/2022
Led by: David Holmgren, Nick Ritar, Kirsten Bradley
Web: www.milkwood.net/courses


INTRODUCTION TO PERMACULTURE COURSES


Led by:    Diana Cole, Bob James
Web:    www.learnhowto.com.au/product-permaculture-concepts-646.aspx


Led by:    Teresa Pereira, Marie Edwards
Web:    https://northernschool.info/intro-permaculture-design-course


Led by:    Giuseppe Tallarico
Web:    https://worldpermacultureassociation.com/learn-permaculture-design-science

SPECIAL COURSES

International Forest Garden / Food Forest Symposium
Venue:    Online
Dates:    31 May - 4 June 2021
Led by:    Agroforestry Research Trust
Web:    www.agroforestry.co.uk/symposium

MUSHROOM CULTIVATION
Led by:    Nick Ritar, Kirsten Bradley
Web:    www.milkwood.net/courses


Advertisement