Culebra lies in a mini-archipelago of 24 chunks of land, rocks, and cays 18 miles east of Puerto Rico's main island, halfway to St. Thomas, U.S. Virgin Islands. At just 7 miles long and 3 miles wide, Culebra has only 2,000 residents. From 1909 to 1975, Culebra was used as a gunnery range for the U.S. military. Today, visitors flock to the secluded white-sand beaches, clear water, and coral reefs. Dewey is the only town on the island and 52 miles from San Juan.