Fort Sumter gets the fame — it's where the American Civil War started, after all — but just across Charleston Harbor on Sullivan's Island sits a fort with an even longer story, and far smaller crowds. Fort Moultrie, part of the Fort Sumter and Fort Moultrie National Historical Park, has guarded the harbour in one form or another since the American Revolution.

The first version was a rough affair of palmetto logs and sand, still unfinished when Colonel William Moultrie's men repelled a British naval attack in 1776. The British eventually took Charleston in 1780, and the fort decayed. A second fort, finished in 1798, lasted just six years before a hurricane destroyed it. The brick fort standing today was modernised through both World Wars to counter submarines and aircraft, then abandoned in 1947 as nuclear weapons made coastal artillery obsolete. Its exhibits now walk you through 171 years of American military history.

Start at the visitor centre, open daily 9 a.m. to 4:30 p.m., where you can grab a self-guided brochure or join a ranger-led tour. Highlights include the three-storey Harbor Entrance Control Post from 1944, complete with signal rooms and observation decks, and Battery Jasper with its disappearing 55-ton rifles. Cannon Walk lines up artillery you can gawp at up close.

There's a sobering layer of history here too. Sullivan's Island was an entry point for enslaved Africans in the 18th century, and the Bench by the Road near the visitor centre, installed in 2008, commemorates them.

Entry costs $10, or is free with an America the Beautiful pass. The fort itself takes a couple of hours, and it sits right by the beach — so once you're done, you can walk straight onto the sand. Halfway along the shore, detour to Charleston Light, a 162-foot triangular lighthouse and the last major lighthouse built in the U.S. The 0.7-mile Sullivan's Island Nature Trail threads through dunes and woodland, with a decent chance of spotting pelicans and mockingbirds. The 1894 Sullivan's Island Life-Saving Station, South Carolina's only one, also sits within the park, though both it and the lighthouse are exterior viewing only for now.

Getting there is easy: about 20 minutes from Charleston across the Ben Sawyer Bridge, with Charleston International Airport just outside the city. If you want more fort action, ferries from Charleston or Mount Pleasant run out to Fort Sumter.

Lodging on the small island is limited — try an Airbnb, head to Isle of Palms, or base yourself in Charleston. For food, Sullivan's Island punches above its weight: the Obstinate Daughter serves award-winning Southern cooking, while Poe's Tavern does gourmet burgers in honour of Edgar Allan Poe, who was stationed at Fort Moultrie in 1827 and set his short story "The Gold-Bug" on the island.

This one's for travellers who like their beach days with substance — history buffs, families mixing education with sandcastle time, and anyone who'd rather skip Fort Sumter's ferry queues for a fort you can drive to. Time your visit for sunset over the harbour and the marshland of the Intracoastal Waterway, and you'll wonder why anyone bothers with the famous one.