THE world’s tallest building is a hotly contested title. From the Empire State to the Sears Tower, Taipei 101 and now the Burj Kalifa, these highly visible structures are known across the world. Less well known, for obvious reasons, are the buildings that extend downwards into the earth. Here we take a dive into this hidden realm to reveal five of the world’s deepest buildings (that we know about).

Ever since early man first took shelter in caves, humans have been using underground spaces. Although the lack of light makes underground buildings unsuitable for many human activities, building downwards can create secure, safe and of course unobserved spaces. We have all heard the rumours of an underground bunker at the Pentagon, although officially at least, the building only has three basement levels.

In our opinion, to be classified as an “underground building” these structures must be man-made for permanent human use, rather than deep level mines. We have also chosen to feature only one building in each typology to demonstrate the variety.

5 – SYDNEY OPERA HOUSE, AUSTRALIA – 120 FEET DEEP

The sails of the Sydney Opera House, one of the world’s most recognizable buildings, soar 200 feet above Sydney Harbour. Less well known is the fact that this building extends almost the same distance underground; beneath this landmark structure is the deepest car park in the world.

Above: Beneath the Sydney Opera House is the deepest car par in the world (image courtesy of Alice Johnson).

A popular solution around the world where space is limited, the cost of construction usually limits underground car parks to around four or five stories deep. However, Sydney Opera House’s car park extends 12 storeys into the earth. At 120 feet (or 37 metres) this is considered the deepest basement in the world.

Above: The huge doughnut shaped car park extends 12 storeys into the earth.

Excavation of the cavern and associated tunnels, which involved removing some 130,000m3 of sandstone started in late 1990 and was completed in April 1992. The huge doughnut-shaped cavern contains a double-helix internal concrete ramp structure that has a capacity for 1,100 cars.

4 – GJØVIK OLYMPIC CAVERN HALL, NORWAY – 180 FEET DEEP

Even deeper than Sydney Opera House’s car park is the Gjøvik Olympic Cavern Hall built for the 1994 Winter Olympics, where it hosted 16 ice hockey matches. With a capacity of 5,500, the world's largest underground auditorium is buried 180 feet (55 meters) beneath a mountain.

Above: Built for the 1994 Winter Olympics, this incredible ice hockey arena is buried within a mountain (image courtesy of Tunnel Talk).



Excavation for the arena saw 4,900,000 cubic feet (140,000 cubic meters) of rock removed in over 29,000 truckloads – 170 tonnes of dynamite were used during the blasting.

It was decided to place the arena underground so that it would not take up valuable downtown land or interfere with the town's cityscape, while still being centrally located. Building underground had the additional benefit of creating a stable year-round natural temperature; reducing the building’s heating and cooling costs.

3 – ARSENALNA STATION, UKRAINE – 350 FEET DEEP

Heading deeper underground we find Arsenalna Station in Kiev. Sitting 350 feet (105 metres) under the city, this station is the deepest underground station in the world.

Above: It takes 5 minutes travelling on an escalator to get to the platform at the world's deepest station.

Arsenalna is as deep as the Statue of Liberty is tall and the journey from surface to platform takes more than five minutes. To put this in context, London’s deepest station is Hampstead at 192 foot (58 metres) deep, while New York’s is 191st Street, which is approximately 180 feet (55 metres) below street level.

The station’s depth is due to the geography of Kiev, where parts of the city stand on a hill with others almost at sea level on the banks of the Dnieper River.

2 – LARGE HADRON COLLIDER, FRANCE / SWITZERLAND – 575 FEET DEEP

Travelling even deeper we find perhaps the world’s most impressive underground structure. Constructed 575 feet (175 metres) below the border of France and Switzerland is the Large Hadron Collider built by the European Organisation for Nuclear Research, better known as CERN.

Above: CERN's Large Hadron Collider was built underground to shield it from background radiation (image courtesy of CERN).



Completed in 2008, the 27km long structure is the world’s largest single machine and its most powerful particle accelerator. Built underground to shield it from background radiation, the collider was designed to explore what happened immediately after the Big Bang.

1 – JINPING UNDERGROUND LABORATORY, CHINA – 7,900 FEET DEEP

The deepest buildings in the world are in fact all research laboratories. Just like the Large Hadron Collider, these structures are built deep into the earth’s crust to enable experiments to take place in conditions with extremely low levels of background radiation.

Above: All of the world's deepest buildings are sciences labs, and at an incredible 7,900 feet deep Jinping Underground Laboratory is the deepest (image courtesy of Tsinghua University).

The deepest of these impressive buildings is the Jinping Underground Laboratory, which is located an incredible 7,900 feet (2.4 kilometers) under a mountain in western China – the equivalent of seven Empire State Buildings stacked on top of one another.

Completed in 2010, the laboratory is an ideal site to do low background neutrino physics research and investigate dark matter.

Although this is the deepest known building in the world, humans have gone deeper. In South Africa the world’s deepest mine extends more than four kilometers into the earth. While at 12.2 kilometers deep (7.5 miles) the "Kola Superdeep Borehole" in Russia is the deepest artificial point on Earth.

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Images courtesy of Alice Johnson, Rob Kashubin, Space Hero, Lillehammer Youth Olympic Games, Tunnel Talk, CERN, Tsinghua University and Anglogold Ashanti. We welcome you sharing our content to inspire others, but please be nice and play by our rules.