Hart Island in the Long Island Sound, New York, where over 700,000 burials have taken place is probably the most densely packed cemetery in America. The majority of the dead bodies are unclaimed or unknown babies. The first body was buried there in 1869, when the body of a 24 year old woman was left unclaimed. Check out the Google Sightseeing page for Island of the Dead, and also take a look at the ground level photo-tour taken in 2000 by a group of historians. The island is not open to the public, so this was a rare opportunity. It's pretty spooky looking at the pictures. With over 700,000 dead bodies lying in the ground, you almost feel like you can expect to find ghosts in the pictures.