Mudjin Harbour, a half-moon cave and a picturesque beach that juts out from the land to link up with an offshore Cay is a most dramatic feature. The huge limestone caves feature stalactites, stalagmites, bats, owls and salt lakes that link up with the sea, and are considered to be one of the most extensive cave systems in the region. There also the remains of huge Lucayan Indian settlements. One site excavated near Armstrong Pond in 1978 contains a Lucayan ball court, unknown elsewhere in the Lucayan islands. Artifacts recovered from the caves suggest that they were used either as shelter or sacred places. Middle Caicos also contains ruins of Loyalist plantations. A Frigate Bird colony resides on a cay Just offshore. A large blue hole just offshore in shallow water features an abundant variety of marine life. The island's Northwest Point is a combination of beautiful inlets, marshes, mangroves and in land ponds which serve as a haven for birdlife.