The first anomalous structure that was discovered at Yonaguni lies below glowering cliffs of the southern shore of the island. Local divers call it Iseki Point ('Monument Point'). Into its south face, at a depth of about 18 metres, an area of terracing with conspicuous flat planes and right-angles has been cut. Two huge parallel blocks weighing approximately 30 tonnes each and separated by a gap of less than 10 centimetres, have been placed upright side by side at its north-west corner. In about 5 metres of water at the very top of the structure there is a kidney-shaped 'pool' and near by is a feature that many divers believe is a crude rock-carved image of a turtle. At the base of the mnoument, in 27 metres of water, there is a clearly defined stone-paved path oriented towards the east.