According to Wikipedia: "Named for a mythical medieval French sword, the Durandal is a anti-runway penetration bomb developed by the French company Matra (now MBDA), designed to destroy airport and airfield runways and exported to a number of countries worldwide. As a simple crater in a runway could be just filled in, the Durandal deliberately utilizes two explosions in order to displace the concrete slabs of a runway, damage that is far harder to repair."