The Mesoamerican Barrier Reef System (MBRS), also popularly known as the Great Mayan Reef or Great Maya Reef, is a marine region that stretches over 1000 km from Isla Contoy at the tip of the Yucatán Peninsula down to Belize, Guatemala and the Bay Islands of Honduras. The reef system includes various protected areas and parks including the Belize Barrier Reef, Arrecifes de Cozumel National Park, Hol Chan Marine Reserve (Belize), Sian Ka'an biosphere reserve, and the Cayos Cochinos Marine Park. Belize's coastline, comprising the Belize Barrier Reef, is home to approximately 80% of MBRS. The Belize Barrier Reef is the largest barrier reef in the northern hemisphere and the second largest barrier reef in the world. The Belize Barrier Reef and Belize's 3 offshore atolls, several hundred sand cays, mangrove forests, coastal lagoons and estuaries - collectively termed, the Belize Barrier Reef Reserve System has been designated a World Heritage Site by UNESCO (1996).