The first successful English colony in America was at Jamestown, Va., a swampy island in the Chesapeake Bay. The colony endured for almost a century, and remnants of the place still exist. You can go there and see the ruins. You can walk where Capt. John Smith and Pocahontas walked. But Jamestown is now threatened by rising sea levels that scientists say could submerge the island by century's end.
By the end of the century, ocean levels could rise by 2 or 3 feet. That's enough to flood the colonists' first settlement at Jamestown, Va.