What's the must-see thing in Charleston?

Fort Sumter sits on a man-made island at the mouth of Charleston Harbor, about 5.6 km from the city's waterfront. Construction started in 1811. The fort was still unfinished when Confederate guns opened fire on its garrison and started a war that lasted four years. What you see today is not a pristine fortification. It's a ruin, compressed by sustained bombardment to roughly a third of its original height. The National Park Service operates the only ferry from downtown, and the round trip runs about 2 hours and 15 minutes with 1 hour on the island. Book the 9:30 a.m. slot online. By early afternoon in August, the fort's brick walls radiate stored heat and there is zero shade on the gun platforms. You'll smell salt water and diesel exhaust from the ferry engine all the way across Charleston Harbor. The ranger talk at the flagpole runs 20 minutes and is the best free introduction to the fort you'll get.

Back on the peninsula, the Battery at the southern tip of the historic district is where Charleston's geography clicks into place. The seawall promenade runs along Murray Boulevard and East Battery, with views across the harbor toward the fort and Sullivan's Island. Antebellum mansions lining South Battery sell for $4 to $12 million, and their piazzas (Charleston's word for side porches, not plazas) carry some of the most detailed cast ironwork still standing in the American South. Walk north from White Point Garden up Church Street and you'll pass the Huguenot Church, built in 1844 as the oldest Gothic Revival church in South Carolina. The full walk from the Battery to Meeting Street covers about 1.6 km and takes 25 minutes without stops. On an August morning the live oaks throw enough shade to keep it bearable, but the humidity still sits near 90% before noon. Carry water.

Emanuel AME Church on Calhoun Street was founded in 1816 by free Black congregants, among them Denmark Vesey. It's the oldest African Methodist Episcopal church in the South. The 2015 shooting added a weight of recent grief that is still present. Sunday services at 9:30 a.m. are open to visitors. The Charleston Museum at 360 Meeting Street, founded in 1773, is the oldest museum in the country. The current building dates to 1980, so don't expect colonial architecture. It compresses the full span of Lowcountry history into a single air-conditioned floor. Admission runs $15, and 90 minutes covers everything. In the wet heat of August, both buildings feel like mercy after 30 minutes on the open street.

Skip Charleston's carriage tours on your first morning. They cost $35 to $45 per person, last about 60 minutes, and the routes are assigned by a random lottery at the departure point. You can't choose which neighborhood you'll see. The guides tend to be good. That said, a carriage ride explains streets like Tradd and Legare that you haven't walked yet, so nothing sticks. Walk first. The USS Yorktown at Patriots Point in Mount Pleasant is a real aircraft carrier from 1943, and kids under 12 tend to rank it above everything else in the city. But it sits across the Ravenel Bridge, and the flight deck in August sun reaches surface temperatures above 50°C. If you go, arrive at opening and plan at least 2 hours.