Which island arcs contain the deepest parts of the Atlantic Ocean?

The deepest parts of the Atlantic Ocean are associated with two primary island arcs: the Lesser Antilles in the eastern Caribbean and the South Sandwich Islands in the South Atlantic.12

These island arcs are characterized by steep-sided, narrow deep-sea trenches where the greatest depths of the Atlantic occur, dropping more than 25,000 feet (7,600 metres) below sea level. Specifically, the Puerto Rico Trench, which joins the Lesser Antilles island arc, contains the deepest point in the Atlantic Ocean, known as the Milwaukee Depth, at approximately 27,493 feet (8,380 metres). Similarly, the South Sandwich Trench is the corresponding deep-sea feature associated with the South Sandwich island arc.231