Mana Pillbox is located in Guam

The Mana Pillbox is an old World War II-era Japanese-built defensive fortification on the east coast of the island of Guam. It is located south of the village of Talofofo, about 50 metres (160 ft) inland from the point marking the south end of As Anite Cove. It is a structure built out of coral limestone and concrete, with an interior chamber about 3 by 1.8 metres (9.8 ft × 5.9 ft) in size. The entrance is on the south side, measuring 0.85 by 1.45 metres (2.8 ft × 4.8 ft). There is one gun port, facing north, measuring 0.32 by .9 metres (1.0 ft × 3.0 ft). The structure was designed to be well hidden in view from the sea and air. It was built, probably by conscripted Chamorro labor, during the Japanese occupation period 1941-44.

• http://en.wikipedia.org/wiki/Mana Pillbox