In order to create new living space and constantly improve the urban infrastructure, supply lines, underground tunnels and car parks are being built. It is not unusual for construction companies to come across old walls and vaults, which are of great interest to archaeologists, especially in city centres. With appropriate detection technology such as ground scanners and cavity detectors, these old tunnels, vaults, wells, cisterns and aqueducts can be discovered and located before civil engineering work begins.
The rediscovered cities of past centuries were covered or replaced in the course of time – some vaults continued to be used and remained intact, others have been forgotton at some point. Often the foundation walls, remains of buildings and galleries are well preserved and protect artefacts and treasures which wait to be rediscovered.
Many stairs lead deep below the Italian capital into underground corridors, tunnels and churches, which have been under the metropolis for 2500 years.
Since the Middle Ages limestone has been mined in the mysterious corridors. The galleries are several kilometres long and lie far below the sewerage system. At the end of the tunnels there are bones of six million people.
Not only the catacombs of Paris and Rome are underground “cities” of a special kind. In Jerusalem, the ancient tradition is being revived: Even today, new underground Jewish cemeteries are still built.
Under the impressive Wailing Wall there are tunnels leading along for about 448 metres. The complex underground tunnels were first discovered by British archaeologists in the 19th century. The actual excavations were carried out 100 years later by the Ministry of Religions.
Under the world-famous Berlin, there is also an underground city: the “Underworld” houses an impressive protection bunker from the Second World War. The numerous corridors and rooms of the bunker complex resemble a labyrinth. Moreover, the Berlin sewage system is one of the oldest, best and largest in Europe.
In the Turkish region of Cappadocia there are underground cities, some of which date back to the 8th century BC. Derinkuyu is the largest and was probably built by the Hittites. The multi-storey labyrinth of ventilation shafts, wells and a wine cellar served 20,000 people as living space and refuge.
About 40 m below ground there is an old city under the “new” city of Naples, which reminds of its Greek and Roman roots. The underground structures reveal paved streets, remains of an aqueduct, shop fronts and a Roman theatre.
Not as ancient as the Roman walls or as old as the Paris catacombs, but still exciting and fascinating: the confusing passages under the South Bridge in Edinburgh. The chambers in the arches of the bridge were used in the 18th century as warehouses, workspaces and living quarters, but were closed in the middle of the 19th century and were forgotton. It was not before 1989 when the chambers filled with historical artefacts have been rediscovered.
Unlike the previous cities, Plymouth, capital of the British overseas territory of Montserrat (Lesser Antilles), was afflicted by a force of nature: The volcano Soufrière Hills erupted several times between 1995 and 1997 and buried the buildings under 1.5 m ash masses.
160 m wide and 480 m long, this awesome concrete island rises out of the East China Sea. From the end of the 19th century to the middle of the 20th century, coal mining attracted tens of thousands of workers to the city, which is surrounded by metre-high protective walls to protect it from waves. Today, Hashima is an industrial monument.