Christmas Island — a tiny Australian territory in the Indian Ocean, about 500 miles south of Indonesia — was named by an English captain who happened to spot it on Dec. 25, 1643. But the island boasts another festive source for its name: At the end of every year, a rare phenomenon sweeps over its natural green terrain, turning it bright red. (WaterFrame / Alamy Stock Photo) Alongside a plethora of exotic tropical creatures and about 2,000 humans, Christmas Island is home to a whopping 50 million bright red land crabs — called the Gecarcoidea natalis — that exist nowhere else in the world. These large arthropods live out most of their days in shady coves within the island's dense forests, but each year, they make one epic journey from the inner jungles to the coast.