Atoll (Civ5)/Civilopedia

An atoll is a formation of coral which creates an island. Atolls are typically ring-shaped, encompassing a central shallow lagoon, and the islands are typically low and small. Atolls are one of the most common island types in the Pacific, the other being islands of volcanic origin. Atolls are akin to oases, in that they are often the only points of land in hundreds of square miles of pelagic expanse. Marine life and birds make ready use of atolls, and though humans have inhabited some, atolls are often hostile for larger land animals. Their low profile means that storms regularly engulf them, and there is often little shade from the powerful sun. As a result of his experiences and observations on the Beagle Voyage, Charles Darwin was the first Westerner to correctly hypothesize how atolls were formed.