Situated in the west of Bosnia on the border with Croatia, Objekat 505, as it was officially known, was the largest underground airport in the Balkans. The primary purpose of the Objekat 505 was to house a long-range radar early warning system, akin to NORAD, as well as to provide a strategic command center for the country’s defense.
The Barbados HARP Gun, was part of Project HARP, short for High Altitude Research Project, which was a joint project of the United States Department of Defense and Canada's Department of National Defence created with the goal of studying ballistics of re-entry vehicles at low cost; whereas most such projects used expensive and failure-prone rockets, HARP used a non-rocket spacelaunch method based on a very large gun to fire the models to high altitudes and speeds.
The complex contains over five hundred nuclear-hardened concrete military bunkers, partially buried underground and protected by thick berms of earth, to resist a surface blast wave, as well as radioactive fallout.
The Kola Superdeep Borehole was a scientific project undertaken by the Soviet Union in the 1970s to better understand the Earth’s crust.
The Cultybraggan camp is one of the last remaining World War 2 Prisoner of War Camp in the UK.
The Berlin Wall was a guarded concrete barrier that physically and ideologically divided Berlin from 1961 to 1989.
About twenty kilometers from the city of Boulogne-sur-Mer, near the hamlet of Mimoyecques, in northern France, lies a once-secret underground Nazi base.
For years, boozers from the Texas A&M University in College Station, Texas, and elsewhere, have been paving a short alley located between the pub Dry Bean and the restaurant Dixie Chicken, with used bottle caps.
Al-Rajajil, sometimes referred to as the Standing Men, or Standing Stones, are a collection of some fifty groups of man-made stone columns near the ancient oasis town of Sakakah in Al-Jawf province in northwestern Saudi Arabia.