In 1654, Oliver Cromwell dispatched a fleet to seize Hispaniola from Spain. The expedition, led by Admiral William Penn and General Robert Venables, was a humiliating failure. Rather than return to England empty-handed, the commanders turned their sights on Jamaica, which Spain held with a token garrison. By May 1655, the island was in English hands. Construction of a fortified stronghold began almost immediately on the narrow sand spit separating Kingston Harbour from the Caribbean Sea. The fort was completed that same year, initially called Passage Fort, and later renamed Fort Cromwell in honor of the Lord Protector. When Charles II was restored to the English throne in 1660, the fort was prudently rechristened Fort Charles. Among the soldiers in the original invasion force was a young Welshman named Henry Morgan, who would go on to become the most famous buccaneer of his age -- and eventually, improbably, the lieutenant governor of Jamaica.

Under Fort Charles's guns, Port Royal grew into something unprecedented. By the 1680s, it was one of the largest and wealthiest cities in the English-speaking Americas, its harbor thick with merchant ships, privateers, and outright pirates. The wealth that flowed through Port Royal came from sugar, from the slave trade, and from the plunder of Spanish shipping that England quietly encouraged through letters of marque. Contemporaries called it "the most wicked and sinful city in the world" -- a reputation earned by taverns, brothels, and a population that spent its fortune as recklessly as it earned it. Fort Charles stood at the tip of the sand spit, its cannons arranged along every other row of the outer wall, guarding the harbor entrance. Five more forts were eventually constructed to defend the town, but Fort Charles remained the principal stronghold, the red-bricked asymmetrical fortification that warned approaching ships not to test their luck.

On June 7, 1692, the ground beneath Port Royal liquefied. A massive earthquake struck at 11:43 in the morning, and the sandy spit on which the city was built simply collapsed into Kingston Harbour. Two-thirds of Port Royal slid into the sea. Roughly 2,000 people died in the initial earthquake and tsunami; another 3,000 perished in the following days from injuries and disease. Of Port Royal's six forts, only Fort Charles survived, though the earthquake left it damaged and partially submerged. The 1692 disaster effectively ended Port Royal's golden age. The city was rebuilt on a smaller scale, struck again by fire in 1703 and hurricanes in 1722 and 1744, and gradually diminished from a capital of empire to a quiet fishing village. Fort Charles was reconstructed in 1699 under Colonel Christian Lilly, chief engineer of Jamaica, and continued to serve as a military installation for another two centuries.

In 1779, with Britain's North American colonies in open rebellion and France threatening its Caribbean possessions, a 21-year-old naval captain named Horatio Nelson was assigned to command Fort Charles. For roughly 30 months, Nelson paced the southern battlement scanning the horizon for the French invasion that never came. That raised platform along the fort's southern wall is still called Nelson's Quarterdeck. The young captain who nervously watched the sea from Port Royal would go on to become Britain's greatest naval hero, dying at Trafalgar in 1805. A century after Nelson's tenure, the earthquake of 1907 struck Jamaica, and while it did not destroy the fort, it tilted the nearby Royal Artillery Store so severely that the building became a tourist curiosity -- the Giddy House, where the slanted floor confuses visitors' inner ears and sends them stumbling. Fort Charles itself endured, as it had endured everything, battered but upright.

Today Fort Charles is a museum and a National Heritage Site, the oldest standing fortification in Jamaica. Its cannons still line the outer walls, pointing across a harbor that has changed beyond recognition since the days when pirate ships anchored in its shelter. Inside the fort, exhibits trace the story of Port Royal from buccaneer haven to earthquake ruin to sleepy fishing community. The sand spit that once held a city of thousands now holds a village of a few hundred. Underwater, the submerged ruins of pre-earthquake Port Royal remain one of the most significant marine archaeological sites in the Caribbean, and UNESCO has recognized the 17th-century archaeological ensemble as a site of outstanding universal value. Fort Charles stands at the edge of all this vanished history, the lone survivor of a place that seemed invincible until the earth itself disagreed.