I believe Earth and Earth Day should be celebrated every day.
Earth Day celebrated its 50th anniversary in April.
Sadly this world wide event had to be done online.
Here is a link to wonderful NASA Earth Day posters
The planetarium look forward to celebrating Earth Day live in the future.
Sierra Club t-shirt
NASA has collected numerous activities to help you observe “Earth Day at Home."
https://www.nasa.gov/content/earth-day-2020
Earth Day Toolkit
https://www.nasa.gov/content/earth-day-2020-50th-anniversary-toolkit
Global Climate Change
Earth at Night images
https://www.nasa.gov/connect/ebooks/earthatnight_detail.html
Earth as Art NASA ebook
https://www.nasa.gov/connect/ebooks/earth_art_detail.html
Earth Day Image Gallery - Celbrating Earth's Beauty
https://www.nasa.gov/content/earth-day-image-gallery-celebrating-earths-beauty
Earth Science Lessons
https://www.jpl.nasa.gov/edu/teach/tag/search/Earth%20science
Apollo Earth Day Posters
July 2019 was the 50th anniversary of the first human landing on the moon.
https://www.lpi.usra.edu/apollo50/index.shtml#resources
Eyes on the Earth - using an app
https://eyes.nasa.gov/eyes-on-the-earth.html
11 Videos, meant for the ISS 20th anniversary, is a series to celebrate the Earth.
https://www.youtube.com/watch?v=5L6eqgnmlPo&list=PLQAvHoeWXY8ltBdS9iRiQUA9yAw9-O2kQ&index=2
Earth - Our Home Planet overview
https://solarsystem.nasa.gov/planets/earth/overview/
50 Years of Earth Day Video
https://m.youtube.com/watch?feature=youtu.be&v=BqA1iXYFRIU
Earth Day at Home for young learners