I believe Earth and Earth Day should be celebrated every day.
Earth Day celebrated its 51th anniversary on April 22.
Sadly this world wide event had to be done mostly online.
Here is a link to wonderful NASA Earth Day posters
The planetarium look forward to celebrating Earth Day live next year.
Sierra Club t-shirt from 2020
Global Climate Change - Vital Signs of the Planet
Earth Day Image Gallery - Celebrating Earth's Beauty
Apollo Earth Day Posters
July 2019 was the 50th anniversary of the first human landing on the moon.
Eyes on the Earth - using an app
11 Videos, collected for the ISS 20th anniversary - a series to celebrate the Earth.
Earth - Our Home Planet overview
50 Years of Earth Day Video