Dry Tortugas National Park - Failed Fort, Hellhole Prison

Just across the arrow channel from Bush Key, on the site of the old lighthouse, sits the Dry Tortugas' most famous landmark, Fort Jefferson. The largest brick fortification in the world, it was begun in 1846 in an effort to protect the United States' vulnerable flank by controlling shipping in the Gulf of Mexico.

In 1861 the fort became a prison for Union Army deserters, who were punished with heat, humidity, disease, and an appalling diet. Doubtless, the prison's most famous inmate was Dr. Samuel Mudd, the Maryland physician sentenced to life behind bars for setting the broken leg of fugitive Lincoln assassin John Wilkes Booth. Mudd tried to escape from the islands, and spent two years in chains for the attempt, but when a yellow fever epidemic broke out in 1867, he rose to the challenge. Mudd labored for three months to save the sick; two years later he earned a presidential pardon for his heroic efforts.

The military finally abandoned Fort Jefferson to the elements in 1873, and although it was used as a quarantine station and a naval refueling post around the turn of the century, it languished until President Franklin Roosevelt proclaimed it a national monument in 1935. In 1992 the Dry Tortugas became a national park, enjoying greater protection for its fragile environment, including one of the most pristine coral reefs in the United States.

Living Cities of Stone
Coral reefs are the marine equivalent of tropical rain forests, jammed with a diversity of life unequaled anywhere else at sea. Slip on a mask, fins, and a snorkel, and you enter a world where schools of multihued fish twist and dodge, gaudy fanworms blossom like red or orange flowers from the coral heads, and spiny lobsters wave their long, whiplike antennae at intruders. Angel fish and butterflyfish, adorned with neon colors, disappear among the culs-de-sac of coral, while squadrons of spotted eagle rays glide past majestically, their shadows playing catch-up across the undulating sandy bottom.

The foundation of the reef is millions of tiny coral polyps, organisms related to jellyfish that have traded freedom of movement for a life of cemented security. The colonies of polyps secrete calcium carbonate to form hard, stonelike structures that vary from species to species, round and corrugated in brain coral, delicate and branched in staghorn coral. It is a painfully slow process, one that may require a century or more to create a graceful candelabra and thousands of years to fashion the intricate, complex reefs that visitors see today.

Still, the rocklike fortress of the coral head is not an impregnable defense for the polyps. Foot-long fireworms, their sides bristling with feathery tufts that conceal sharp spines, browse on the living coral, leaving white, denuded areas in their wake. Parrotfish use their beaklike mouths to feed on the coral rock, swallowing grit and polyps alike.

Such natural predators pale, however, beside human threats. Even a careless touch by curious divers can damage living coral, to say nothing of the wreckage a dragging boat anchor can cause. Overuse, sediment, and pollutants have decimated many reefs in Florida and the Caribbean, but thanks to its isolation, the park has exceptionally clean, clear water and the healthiest reefs in the region. Day by sun-drenched day, the coral polyps of the Dry Tortugas slowly improve on their work of centuries, creating new marvels beneath the waves.