The Dipnaysupuan Japanese Tunnel is located in the Tukon Hills area in Basco, Batanes Province. The Dipnaysupuan Tunnel is an interconnected network of tunnels built during the Japanese occupation of the country for the refuge of Japanese soldiers and lookout post on Batan Island. It served as a shelter for the Japanese imperial forces during the Japanese occupation in the Philippines until the end of World War II. Because of its strategic location, the Japanese imperial forces forced the Ivatans to dig these tunnels for their shelter. The Japanese soldiers spent years hiding in these tunnels until the end of Word War II. There are five doors to the tunnel and it has several chambers. The entrance is low and one has to duck-walk towards the back until one can stand up. It is cold and damp and chilly inside.