It has been dubbed the "Diving Capital of the World" as the living coral reefs, a few miles offshore, attract thousands of scuba divers, sport-fishing enthusiasts and scientific researchers each year.

Automotive and highway pioneer (and Miami Beach developer) Carl G. Fisher built the Caribbean Club in 1938 as his last project.

[2] When Europeans first arrived in the Florida Keys in the 16th century, the area was uninhabited or only sparsely inhabited by indigenous peoples such as the Calusa and the Tequesta.

The earliest description of the area and its inhabitants was by Hernando de Escalante Fontaneda, a survivor of a shipwreck who lived among the Calusa people from 1549 to 1566.

[3] The earliest reference to Key Largo is found on a map prepared in 1639 by Dutch cartographer Johannes Vingboons, in which it is named Caio des 12 Leguas (islet of twelve leagues).

[10] After the film's success, pressure from local businesses resulted in a change in the name of the post office serving the northern part of the island, from "Rock Harbor" to "Key Largo", on June 1, 1952.

[11] The island of Key Largo is an exposed, fossilized remnant of a coral reef formed during a period of higher sea level and then uncovered and eroded during a subsequent ice age.

Inland, decomposed vegetation forms a rich, acidic humus soil up to about 6 in (15 cm) thick, topped by "leaf litter".