During my time at Francis Marion I've heard stories about Florence being the only American city that has had a nuclear bomb dropped on it. I've done a little research on that and found

The government says: No. 13, March 11, 1958/B-47/Florence, South Carolina On March 11, 1958 at 3:53 p.m. Eastern Standard Time, a B-47E departed Hunter Air Force Base, Georgia as number three aircraft in a flight of four enroute to an overseas base. After level off at 15,000 feet, the aircraft accidentally jettisoned an unarmed nuclear weapon which impacted in a sparsely populated area 6-1/2 miles east of Florence, South Carolina. The bomb's high explosive material exploded on impact. The detonation caused property damage and several injuries on the ground. The aircraft returned to base without further incident. No capsule or nuclear materials was aboard the B-47 or installed in the weapon. 

CDI says: Accounts of this widely reported accident describe the bomb falling in garden of the home of Mr. Walter Gregg in Mars Bluff, S.C. The high explosive detonation virtually destroyed his house creating a crater 50-70 feet in diameter and 25-30 feet deep. It caused minor injuries to Mr. Gregg and five members of his family, and additionally damaged five other houses and a church. The clean-up effort required several days. Air Force personnel recovered hundreds of pieces of bomb fragments that were carried off as souvenirs by local residents. The inhabitants of Mars Bluff were examined for several months to see if they had been exposed to any radiation. Five months later the Gregg family was awarded $54,000 from the Air Force. After this accident Air Force crews were ordered t "lock in" nuclear bombs. This reduced the possibility of accidental drops but increased the hazards if the plane crashed. (http://www.milnet.com/milnet/cdiart.htm)

Will says: After following a lot of well-meaning but incorrect directions Paula and I finally pedaled our bikes to the bomb crater less than a mile from Francis Marion University. We were somewhat uncomfortable when we found that someone had a pit bull tied up in the woods next to the crater and a house and chain for another dog. It doesn't look like much but here it is.

March 23, 2004 I revisited the site to get a GPS reading. Several dogs are tied up next to the crater. The area, which sits behind an empty mobile home lot,  is not posted so I suspect the dog owners have taken up temporary squatters rights. The coordinates are:
North 34 12.046'
West 079 39.420'

http://www.milnet.com/milnet/cdiart.htm