The Lesser Antilles (also known as the Caribbees) are a long, partly volcanic island arc in the Caribbean Sea. Most of its islands form the eastern boundary of the Caribbean Sea with the Atlantic Ocean, with the remainder located in the southern Caribbean just north of South America. The Lesser Antilles and the Greater Antilles compose the Antilles, which are in turn part of the West Indies along with the Bahamas, the Cayman Islands, and the Turks and Caicos Islands.