Excelsior Tunnel

In 1959 it was the centre of project Military Atomic Energy Authority operation orpheus investigating the possibility of masking the seismic signal given out by underground nuclear tests.

Barbados HARP Gun

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 Kauri Driving Dams

Some 3,000 driving dams once existed throughout New Zealand, with the last built during the late 1930s. As the timber industry dwindled, gradually the dams decayed and disappeared and now only a few remain as relics of this destructive industry.

Prora

Prora, also known as the Colossus of Prora, is an enormous building complex on the island of RĂ¼gen, Germany, that was built by Nazi Germany between 1936 and 1939 as a beach resort of the Strength Through Joy (Kraft durch Freude or KdF) project.

Suakin Island

The island town of Suakin, in north-eastern Sudan, was an important port for trade and culture on the East African coast for centuries.

Stelling van Amsterdam

The Stelling van Amsterdam was the most advanced military structure of its type in the world – 135 km (84 miles) of forts, batteries and moats completely encircling the city in a defensive barrier.

The Al-Rajajil Standing Stones

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.

The Bottlecap Alley

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.

Kinzua Bridge

The Kinzua Bridge or the Kinzua Viaduct was a railroad trestle that spanned Kinzua Creek in McKean County in the U.S. state of Pennsylvania. The bridge was 301 feet (92 m) tall and 2,052 feet (625 m) long. Most of its structure collapsed during a tornado in 2003.