Query: Kathmandu valley contains art made of metal, terracotta, wood and what other substance?
Context: Kathmandu valley is described as "an enormous treasure house of art and sculptures", which are made of wood, stone, metal, and terracotta, and found in profusion in temples, shrines, stupas, gompas, chaityasm and palaces. The art objects are also seen in street corners, lanes, private courtyards and in open ground.