While technically a region of the North Atlantic Ocean, the Sargasso Sea is unique in the world of geography because it is the only sea that has no land boundaries. Instead of being defined by coastlines, its borders are formed by four distinct ocean currents: the Gulf Stream to the west, the North Atlantic Current to the north, the Canary Current to the east, and the North Atlantic Equatorial Current to the south. This system of currents creates a massive clockwise-rotating gyre. The sea is named after 'Sargassum,' a type of free-floating seaweed that accumulates in massive mats across its surface. This unique ecosystem provides a critical habitat for a variety of marine life, including eels that migrate from Europe and North America to spawn here. Historically, the Sargasso Sea was a source of mystery and fear for early sailors, including Christopher Columbus, who feared that the thick mats of seaweed would trap their ships or hide dangerous reefs.