We visited Fort Sumter, where the American Civil War began in 1861
Admired the tropical vegetation ...
... and wildlife at Magnolia Plantation
and marvelled at the gorgeous old houses in the historic district ...
... not to mention the churches
Charleston was a charming city, though we suspect the weather wouldn't suit us. It was autumn [fall], yet still very hot and humid. We also visited the farmers' markets and Charleston City Market, ate at some gorgeous wee cafes, and enjoyed a very upmarket dinner at the fabulous FIG restaurant.
If you want to get a sense of the city but avoid the air miles, may I recommend the tea shop mysteries by Laura Childs? They're set in Charleston and incorporate many local festivals, as well as historical and geographical tidbits. Good fun, if you're a fan of mystery fiction!