Red Crab Migration
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. Because their larvae cannot survive outside water for the first few weeks after hatching, the terrestrial crabs must trek out to the ocean to breed and spawn. During this mass migration, the island's streets, sidewalks, and beaches are blanketed in crimson claws.
"They swarm over the island, across roads, through homes and schools, under every foot, every tire, inside unattended shoes and covering every surface available," Atlas Obscura reports.
Source: The Week