Inside of Clifford Tower. On our ghost tour, the guide said that there was a horrible massacre of the Jews in the 11th century here. So every hundred years, on the day of the massacre, the walls ran red with blood. In the 17th century, Oliver Cromwell invited the Jews back into York, and the blood stopped flowing after that. But you can see some of the stones look pink. The guide told us that the buildings across from the tower, the stones were quarried from the same place at the same time, and those stones remain white. Further proving that the walls really did run with blood. Interesting stuff.