A Kugel ball is a sculpture consisting of a large granite ball supported by a very thin film of water. Water flows beneath a very heavy, perfectly spherical rock from a spherical concave base with the exact same curvature. A Kugel ball can weigh thousands of pounds, but because the thin film of water lubricates it, the ball spins. In 2003 the Science Museum of Virginia unveiled the Grand Kugel, the world's largest kugel ball at a cost of $1.5 million dollars. The Grand Kugel was originally carved from an 86-ton block of South African black granite. It was 8 feet, 8.7 inches in diameter, and it floated on a base of granite. Shortly after installation, the Grand Kugel began to crack. The crack eventually spread through the sphere, rendering it unfloatable. A replacement kugel ball was installed in October 2005. The original kugel is still on display behind the museum.