Another environmental concern is that traditional burial takes up a great deal of space. In a traditional burial, the body is buried in a casket made from a variety of materials. In the United States, the casket is often placed inside a concrete vault or liner before burial in the ground. While individually this may not take much room, combined with other burials, it can over time cause serious space concerns. Many cemeteries, particularly in Japan and Europe as well as those in larger cities, have run out of permanent space. In Tokyo, for example, traditional burial plots are extremely scarce and expensive, and in London, a space crisis led Harriet Harman to propose reopening old graves for "double-decker" burials. Some cities in Germany do not have plots for sale, only for lease. When the lease expires, the remains are disinterred and a specialist bundles the bones, inscribes the forehead of the skull with the information that was on the headstone, and places the remains in a special crypt.