Correction appended, April 22.
Since Earth Day was established in 1970, the annual event has focused on raising awareness and inspiring action in the face of countless threats to the natural environment. In the years since, as climate change has come to dominate headlines, the urgency of those goals has only grown stronger.
This Earth Day, test your knowledge of some of the stunning natural wonders the holiday aims to protect, as they were captured by LIFE magazine’s master photographers.
Correction: The original version of this story misidentified the image of Ama Dablam.