On March 14, 2011 the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite captured this natural-color image of the Island of Bermuda glowing like a gem in the Atlantic Ocean. Sandy beaches along the southeastern edge of the islands appear bright white, while the rest of the island is slightly duller white, colored by a landscape rich in human development. In the northwest, an arch of submerged reefs appears a bright turquoise blue.
Although the land may appear solid at this resolution, the “island” of Bermuda is actually an archipelago, containing about 180 separate islands with a total area of about 53 square km (20.6 sq mi). The largest , Main Island, is sometimes called “Bermuda” in its own right. The archipelago has been known by various names throughout history: La Garza, Virgineola and the Isle of Devils, the latter probably due to legends of spirits and devils inhabiting the island, which may have arisen from the wailings of raucous-voiced birds and the nocturnal noises of wild hogs, as well as the ring of treacherous reefs that proved extremely perilous in stormy weather.
The archipelago was created by activity of volcanoes of the Mid-Atlantic ridge, a submarine mountain range. This ridge formed on a fault line where Atlantic Oceanic tectonic plates expand, pushing the Old and New Worlds apart from each other. Underwater earthquakes and volcanic activity built large underwater mountains, from which lava flowed, raising the land.
The base of the Bermuda archipelago is igneous, but it is now covered by a limestone cap which was formed by marine organisms as they laid down huge amounts of calcium as they grew on the igneous volcanic caldera edges. During ice ages, when sea levels were low, the limestone was exposed to air and erosion, broken down into sand and then blown into dunes. Eventually the dunes hardened into sandstone, forming islands. Such islands are called “atolls”, and while atolls are not uncommon in the Pacific, Bermuda is the only atoll found in the Atlantic Ocean.