One of the most recognizable landmarks in the remote Galapagos Islands, the rock formation known as “Darwin’s Arch,” has collapsed into the Pacific Ocean. The stunning scene happened Monday as travelers on a tour boat to the area watched.

Ecuadorian officials cite natural erosion as the cause cited of the collapse, but scientists and conservationists have long warned that climate change is a major threat to the Galapagos’ delicate eco-system. As the waters around the island chain warm-up, it poses great jeopardy not just to its vast species of marine wildlife, but also to the natural infrastructure, like rock formations.

The natural rock formation is roughly 600 miles from the mainland of Ecuador, and about a mile from an uninhabited island known as Darwin Island. Both are named for the scientist Charles Darwin, whose studies of the exotic species in the Galapagos in 1835 had a major impact on his theory of evolution and natural selection.

Darwin’s Arch is a popular destination for divers and boat tours, because of its abundance of marine life, such as sharks, manta rays, and turtles. Many people expressed their dismay at the news that this famous landmark of the Galapagos is gone, including world-renowned chef Jose Andres.