Photo of the Day

Associated Press
In this Nov. 4, 2015 photo, Dr. Salvador Arias sits during an interview with the Associated Press, inside the botanical gardens of the National Autonomous University of Mexico in Mexico City. About a third of the world's cactus species are threatened with extinction, the International Union for Conservation of Nature warns in a new report.(AP Photo/Rebecca Blackwell)

View gallery

500 photos

View Comments (2)