The Sargasso Sea is the only sea with no land coastline, according to the International Hydrographic Organization. It is a broad region of the North Atlantic defined by ocean currents rather than by bordering continents or islands. The North Atlantic Current, Gulf Stream, North Atlantic Equatorial Current and Canary Current help form its boundaries.
The sea is named for Sargassum, a floating brown seaweed that gathers at the surface. Portuguese sailors noticed these mats during Atlantic voyages, and the vegetation became a distinctive feature of descriptions of the region. The sea is not a sharply bounded patch visible on every map; its limits shift with currents and scientific definitions.
The Sargasso Sea is also important ecologically. It provides habitat for floating organisms and serves as a nursery area for some marine animals, including European and American eels during parts of their life cycles. It should not be confused with the Bermuda Triangle, which is a separate popular geographic concept.