Isla San Marcos - Mexico
Isla San Marcos lies just off San Lucas Cove, between Santa Rosalia and Mulege on the cost of the Sea of Cortez. It boasts some great diving and there is a beautiful cove for swimming, snorkeling, scuba diving and kayaking, and a broad arroyo leading into the interior, with intriguing desert plants and good opportunities for bird watching. They have been mining gypsum on the island since 1926. The village on the island is well established and has its own school and even a small church that the people made in 1950 out of baked blocks of gypsum powder.