Ecuador's naturally formed rock archway, Darwin's Arch (about 600 miles west of Ecuador's mainland), collapsed Monday. Now just two rock pillars stand, with a heap of rubble in between. The cause of the collapse is believed to be due to natural erosion.
From Ecuador's environment ministry Facebook page:
"This event is a consequence of natural erosion. Darwin's Arch is made of natural stone that at one time would have been part of Darwin Island, which is not open to visits by land.
"This site is considered one of the best places on the planet to dive and observe schools of sharks and other species."