Ipao Pillbox I - Credit: Wikimedia Commons
The Ipao Pillbox I is one of three surviving World War II-era fortifications on Ypao Point, located west of Tumon Bay on the west side of the island of Guam. It is built into the limestone cliff overlooking the beach on the property of the Hilton Hotel, about in from the high tide line. Its walls are fashioned out of coral rock and cement, varying in thickness from to . Its entrance is on the east wall, and its gun port faces north, overlooking Ypao Channel. Parts of the structure have been restored. Read more on Wikipedia
Source: en.wikipedia.org