Kenilworth Castle

Kenilworth shows what water could do for a castle. Its sandstone great tower dates to the 1120s, but the real defense was a huge man-made lake, the mere, that surrounded the site and made it hard for attackers to dig beneath the walls. That was put to the test in 1266, in an extraordinary six-month siege, one of the longest in English medieval history. The garrison only surrendered to the king on December 13, 1266. The mere was later drained, so today you look across fields where the water used to be, which makes it easy to picture how wide a barrier it once was. The red stone ruins of the tower and later ranges are extensive and very walkable.