The majority of the Islands of The Bahamas lie atop two giant mounds of limestone that rise off the sea floor: the Little and the Great Bahama Banks. The smaller Little Bahama Bank lies on the northern side of the country and contains the large islands of Grand Bahama and Great Abaco as well as the popular Abaco Cays. Its edges are lined with extraordinary reefs and the protected shallow waters of the Bank, the Sea of Abaco and the Bight of Abaco are ripe for exploring by boat.