Batu Caves is located within a large hill of marble and limestone approximately seven miles north of, and overlooking, Kuala Lumpur. The rock itself is about 400 million years old. The caves were first used by prehistoric men and more recently the "orang asli" (aboriginal people) living in the area. Wooden steps were first built in 1920 to provide easier access to the cave entrance. These steps were replaced in 1940 with the 272 stone steps in place today. During the Japanese occupation, the caves were occasionally used by members of the communist-led Malayan Peoples' Anti-Japanese Army.