Image by JB Carillet Lonely Planet
Right in the middle of the island, there's a wrecked LVT A1 tank that was lost in action when US Marines overran a nearby Japanese stronghold in 1944. Behind the tank, a flight of stairs leads to a small natural limestone cavern, quite hidden behind a tangle of vegetation. Inside lies a large 200mm gun, perfectly preserved. It was used by the Japanese to protect the airfield.