In July, I went to Nis (Ni/Ниш). One of the places I got to see was the Skull Tower. The picture to the left is of one of the skulls in the tower.
Back in 1809, the Serbs were fighting the Turks to drive them out of the area. They had a battle around Nis. From what I understand, the Serbs were loosing the battle and about to be slaughtered. The commander of the Serbs had his men blow up their remaining stores of powder. This, in addition to killing the Serbs, killed a large number of Turks too. In retaliation, the Turks took the bodies–specifically the skulls–and built the tower (about a 12 foot x 12 foot x 12 foot cube). They took the skin off the heads, stuffed them, and sent them back to turkey. The skulls were embedded into the tower as a threat to the Serbs.
Is it creepy? yes. However, when you see it, and realize it happened a few dozen years before the Civil War (and not 500 or 800 years ago), you get a different perspective on time and what is old and recent in Europe.
[Update 08-18-2009 08:09:03] You can go here to see more pictures of the skull tower.