Sargasso Sea

The only sea defined by ocean currents rather than coastlines/Oceans & Seas

The Sargasso Sea is unique among Earth's seas: it has no land boundaries, instead being defined by four ocean currents that form the North Atlantic subtropical gyre. Covering about 3.1 million square kilometers in the western North Atlantic, it is named for the floating Sargassum seaweed that accumulates on its surface. The sea is remarkably clear (visibility up to 60 m) and calm, and serves as the spawning ground for both European and American eels, which make epic migrations to breed here. The Bermuda Triangle overlaps its western edge.