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Mirny Diamond Mine

The Mir mine, also called the Mirny mine, is an open pit diamond mine located in Mirny, Sakha Republic, in the Siberian region of eastern Russia. The mine is >525 meters (1,722 ft) deep (4th in the world) and has a diameter of 1,200 m (3,900 ft), and is one of the largest excavated holes in the world.

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.

Borovsko Bridge

The Borovsko Bridge is an unfinished highway bridge near Borovsko , part of Bernartice municipality, Central Bohemian Region, Czech Republic. It is commonly known as the "Czech Avignon" or "Hitler's Bridge".

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.

Prora

Prora, also known as the Colossus of Prora, is an enormous building complex on the island of Rügen, 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.

Vajont Dam

The Vajont Dam (or Vaiont Dam) is a disused dam in Italy, which was completed in 1959. On 9 October 1963, during initial filling, a massive landslide caused a man-made megatsunami in the lake in which 50 million cubic metres of water overtopped the dam in a wave 250 metres (820 ft) high, leading to 1,910 deaths and the complete destruction of several villages and towns.

Kola Superdeep Borehole

The Kola Superdeep Borehole was a scientific project undertaken by the Soviet Union in the 1970s to better understand the Earth’s crust.

Barbarastollen Underground Archive

Germany’s “treasure chamber” is located in a disused mine near Freiburg. Documents from over a thousand years of history are stored in the underground archive.

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 Petra Treasury

Al-Khazneh is one of the most elaborate temples in the ancient Arab Nabatean Kingdom city of Petra. As with most of the other buildings in this ancient town, including the...

London Post Office Railway

The Post Office Railway, known as Mail Rail since 1987, is a driverless underground railway that was built to move mail between sorting offices.

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.

The Buddhas of Bamiyan

On the cliff face of a sandstone mountain, visible from the ancient Silk Road near the town of Bamiyan in Afghanistan, are two massive voids left by two monumental statues of Buddha that once stood there.

The Soledar Salt Mines

Some 250 million years ago, a part of Ukraine was under a shallow ocean. When the ocean dried up, it left behind a huge deposit of salt.

The Berlin Wall

The Berlin Wall was a guarded concrete barrier that physically and ideologically divided Berlin from 1961 to 1989.