ANTONIO LÓPEZ | Tungsteno
Looking ahead, it could help us survive the threat of overpopulation and climate change, or colonise other worlds, starting with the Moon. But life beneath the surface already has revolutionary applications underway today, taking up the torch from different civilizations across the globe and throughout history that have built underground in search of thermal and acoustic insulation, or a refuge from earthquakes, wars or nuclear accidents.
The remains of majestic underground constructions all over the world are the best way to understand the evolution of the use that has been given to the subsoil. On the island of Kish (a very arid region of Iran) is found the Qanat (or Kariz in Persian), an underground architectural site that preserves a complex network of aqueducts by which water was distributed throughout the region. The walls are covered with several layers of shells and corals that served to filter and neutralise the acids in the water. Qanat technology, which does not require energy to transport the water, spread throughout the world after it was developed by the Iranians in the first millennium BC.
But if there is one region that is most prolific in terms of underground construction, it is Cappadocia in Turkey, where the very soft and stable volcanic tuff rock has facilitated the extraction of the material since the Bronze Age, when cities like Derinkuyu, the largest of all those discovered so far (more than 30), were built. The city had a complex ventilation system, an internal blockage system and oil storage facilities to illuminate the galleries.
The Turkish city of Derinkuyu was an 18-storey deep maze equipped so that 20,000 people could survive inside if the enemy attacked. Credit: Wikimedia Commons.
‘Earthscrapers’, tunnels and underground parks
In addition to the exotic settlements that history has left as a testimony to life underground, today many cities are looking towards the future from beneath the surface and are beginning to move part of their urban activity there. Toronto's PATH network, considered the world's largest connected underground space, or Montreal's underground pedestrian network (RÉSO), with kilometres of tunnels filled with shopping galleries and entertainment areas, are examples of how development below ground is coping with Canada's frigid winters.
In Hong Kong, the commitment to subterranean buildings is not due to severe weather, but to an extreme shortage of space. The city government is encouraging the excavation of the surrounding mountains to create industrial parks and leisure areas. Also in search of more quality living space, New York City is planning the world's first underground park, The Lowline, where vegetation will be able to grow naturally thanks to a sunlight filtering system. A remote skylight and a parabolic collector will direct light to different reflective surfaces underground that will illuminate the space during the day.
In order to preserve the aesthetics of those cities that require habitability solutions in their historical centres, building underground is an alternative that is already beginning to be considered in large urban areas such as Mexico City. In the Mexican capital, the architects at BNKR have designed (but not built) an inverted pyramid 300 metres deep called Earthscraper with a skylight on the surface that would allow natural light to be filtered down to all levels.
The lack of space in the cities, and in anticipation of a future with an adverse climate leads to proposals such as The Lowline in Manhattan, the first underground park in the world. Credit: The Lowline Project.
The subsoil: an ideal environment for scientific research
Another reason to build underground is to take advantage of the specific conditions it meets for scientific research. The subsoil isolates scientific experiments from "noise" and interference that occur on the surface, such as cosmic rays or background radiation from the universe. Thanks to this special isolation, there are currently hundreds of subterranean laboratories scattered across the planet, such as the Large Hadron Collider (CERN), located at a depth of 175 metres in Geneva (Switzerland).
In this regard, a potential underground science development, the USC (Underground Science City), has been proposed for Singapore beneath Kent Ridge Park. This subterranean science community (with 40 caverns connected to laboratories and data centres) would house up to 4,200 scientists and researchers in its 300,000 square metres of facilities, and at a depth of up to 80 metres below the surface. Singapore is growing fast and has a complicated orography, a fact that when added to the exceptional conditions offered by the subsoil for carrying out scientific research makes the proposed science city the perfect plan for deepening a new urbanism.