Elephants eat and roam free at the Elephant Nature Park in the mountains of northern Thailand, near Chiang Mai in 2013. Photo: Lillian Cunningham, The Washington Post 
Tourists flock to Angkor in Cambodia - home to one of the largest operating archaeological sites in the world - to marvel at massive Khmer Empire ruins and ride elephants. For a price, you, too, can sit atop one of these majestic creatures as it carries you around the Angkor Wat temple complex.

Elephant riding has long been the target of criticism from animal activists, who call the practice cruel and harmful. Now, those activists are calling for an end to elephant rides after an elderly female named Sambo collapsed last week after carrying tourists around the historic site.

Sambo, thought to be between 40 and 45 years old, suffered from heart failure after working in extreme heat, Angkor Elephant Company owner Oan Kiri told the Associated Press.