Copyright protection is not forever, at some point the protection expires and works enter the public domain.
Works in the public domain are collective cultural inheritance. Before the complexities of copyright law, Intellectual Property and Patents works were largely public. It wasn’t until mid-18th century that the term “public domain” came into use.
Today, when a creative work’s copyright protection ends, the work enters the public domain, free for all to use, without permission, indefinitely. Works in the public domain are not protected by intellectual property law including copyright, trademark or patent. The public owns this work, the work cannot be owned by an individual. Length of copyright terms vary from country to country. The US is life plus 70 years, Canada is 50 years following a creator’s death, length of copyright terms by country can be found here.

“[Melies color Voyage dans la lune]https://commons.wikimedia.org/wiki/File:Melies_color_Voyage_dans_la_lune.jpg)" by Georges Méliès is in the Public Domain)
A strong public domain is the basis for a creative society. New uses can be built and work can be expanded. There are 4 common ways a work arrives in the public domain
Works in the public domain have resulted in many interesting and creative works. The Digital Public Library Association runs an annual gif competition using images in the public domain.

“Dissension” by Tobias Rothe is licensed CC BY
Following step costs and complex systems clearing music rights, comedian James Corden host of the Late Late Show began a segment where his famous guests perform songs in the public domain. Here is actor Jamie Foxx American actor, singer, songwriter, and comedian performing Twinkle Twinkle Little Star.
:Public Domain Songs w/ Jamie Foxx” by The Late Late Show with James Corden
Think about items you interact with in your everyday life and public domains you experience in your everyday life. Identify an object in your life that is a piece of the public domain.
“Creativity always builds on the past” is a common theme when talking about the public domain—those works which are free to use and re-use without any restrictions. You can learn about this theme on by watching the video Building on the Past.
Pamela Samuelson Professor of Law and Information Management at the University of California, Berkeley has identified eight “values” that can arise from information and works in the public domain.
The world did not alway live in the current complexity of copyright laws. Public domain reacts differently with different mediums, books, music, film. Read this Wikipedia page on “public domain” in relation to intellectual property laws.
Detailed overview of the concept of public domain can be found at the Stanford University Libraries, on the Teaching Copyright website.

Creative Commons public domain legal tool buttons, via https://creativecommons.org/about/downloads/
One of the four ways previously mention for a work to arrive in the public domain is for a creator to dedicate it to the public domain.
Creative Commons has a tool that allows for easy dedication to the public domain called CC-0. Read about the legal tools provided by Creative Commons in support of the public domain, including the CC0 Public Domain Dedication, and the Public Domain Mark. Review CC’s Guide to using public domain tools.
With millions of creative works whose copyright has expired—and thousands more added each week with tools like the CC0 Public Domain Dedication, the size of the public domain is huge! As of 2015, there were over 35 million works marked as in the public domain using the Creative Commons tools.

image from 2015 State of the Commons report by Creative Commons is licensed CC BY
Sites that host works in the public domain include
There are organizations and initiatives work to protect and extending the public domain.
Select two or three resources directly relevant to your personal or work-related CC needs from the Acquiring Essential Knowledge content and add them to your personal Creative Commons toolkit. Adding them to your toolkit makes them easy to find and use when the need arises, and makes it easy for you to pass on resources you consider important to others. Annotate the resources with notes explaining why they are relevant and important for you and your work.
In the CC Certificate social forum post your answers to the personal reflection questions posed at the start of this learning unit. Identify and comment on posts from at least two others who have similar needs or ideas.
Complete the following activity in the Quest Bank:

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Creative Commons Certificates have been created with the kind support of Creative Commons, the Institute of Museum and Library Services, and the Bill & Melinda Gates Foundation.