Underground cities are subterranean settlements that have been constructed throughout history for various reasons, including defence, shelter, and religious or cultural purposes. These cities can range from simple cave dwellings to complex, multi-level structures that can house thousands of people and include amenities such as ventilation systems, water supplies, and storage areas. In recent years, there has been a renewed interest in underground cities as a potential solution to the challenges of urbanization, overpopulation, and climate change.
History of Underground Cities
Ancient Underground Cities
The concept of underground cities is not new; in fact, they have existed for thousands of years. One of the earliest known examples is the underground city of Derinkuyu in Turkey, which dates back to the 7th or 8th century BCE. This city was built by the Phrygians, an ancient Indo-European people, and could house up to 20,000 people. It featured a complex network of tunnels, chambers, ventilation shafts, and amenities such as churches, stables, and storage rooms.
Another notable ancient underground city is the Orvieto Underground in Italy, which the Etruscans built in the 6th century BCE. This city was constructed beneath the hill town of Orvieto and features a network of caves, tunnels, and wells that were used for storage, defence, and water supply.
Medieval and Early Modern Underground Cities
Underground cities were often built for defensive purposes during the Middle Ages and early modern period. For example, the underground city of Lalibela in Ethiopia was constructed in the 12th century as a "New Jerusalem" after the Muslim conquest of the Holy Land. This city features 11 rock-hewn churches that were carved out of solid volcanic rock and connected by a network of tunnels and passageways.
In Scotland, the underground city of Mary King's Close in Edinburgh was built in the 16th century and served as a refuge during the plague epidemics of the 17th century. This city was built beneath the streets of Edinburgh and consisted of a network of narrow alleyways, tenement buildings, and storage vaults.
Modern Underground Cities
In the 20th and 21st centuries, underground cities were built for various purposes, including military defense, scientific research, and commercial development. One of the most famous examples is the Underground City of Montreal in Canada, built in the 1960s to connect the city's downtown buildings and provide shelter during harsh winters. This city features a network of tunnels and chambers that span over 32 kilometres and include shops, restaurants, museums, and even a hockey arena.
Another modern example is the Subtropolis in Kansas City, Missouri, which is a 5.5 million square meter industrial park built in a former limestone mine. This city features a network of roads and tunnels that allow businesses to operate underground, taking advantage of the constant temperature and humidity levels.
Benefits of Underground Cities
Protection from Natural Disasters
One of the main benefits of underground cities is their ability to protect from natural disasters such as earthquakes, hurricanes, and tornadoes. Because they are built beneath the surface of the earth, underground cities are less vulnerable to the effects of these disasters than above-ground structures. In addition, underground cities can be designed with reinforced walls and ceilings that can withstand the force of seismic activity or high winds.
Energy Efficiency
Another benefit of underground cities is their potential for energy efficiency. Because the temperature underground remains relatively constant throughout the year, underground cities require less energy for heating and cooling than above-ground structures. This can lead to significant cost savings and a reduction in greenhouse gas emissions.
In addition, underground cities can be designed to take advantage of geothermal energy, which uses the heat from the earth's core to generate electricity and heat buildings. This renewable energy source is both clean and sustainable, and can help reduce reliance on fossil fuels.
Space Savings
Underground cities can also help to address the problem of limited space in urban areas. By building downward instead of outward, cities can create additional living and working spaces without the need for land acquisition or the displacement of existing communities.
In addition, underground cities can be designed to be highly efficient in their use of space, with compact living quarters and shared amenities such as kitchens and bathrooms. This can help to reduce the overall footprint of the city and minimize the impact on the surrounding environment.
Protection from Extreme Weather
Underground cities can also protect from extreme weather conditions such as heat waves, cold snaps, and air pollution. Because the temperature underground remains relatively constant, underground cities can offer a comfortable living environment even during periods of extreme heat or cold.
In addition, underground cities can be designed with advanced ventilation systems that filter out pollutants and maintain a high level of air quality. This can be particularly beneficial in cities with high levels of air pollution, such as those in developing countries.
Challenges of Underground Cities
Structural Integrity
One of the main challenges of building underground cities is ensuring their structural integrity. Because they are built beneath the surface of the earth, underground cities are subject to the forces of gravity and the pressure of the surrounding soil and rock. This can lead to issues such as cave-ins, sinkholes, and other structural failures.
To address these challenges, underground cities must be designed with robust support systems such as reinforced concrete walls, steel beams, and anchoring systems. In addition, the construction process must be carefully planned and executed to minimize the risk of structural failure.
Ventilation and Air Quality
Another challenge of underground cities is ensuring adequate ventilation and air quality. Because underground spaces are enclosed and have limited access to fresh air, they can quickly become stale and stuffy without proper ventilation.
To address this challenge, underground cities must be designed with advanced ventilation systems that can circulate fresh air throughout the space and remove stale air and pollutants. This can include the use of fans, ducts, and filters to control airflow and maintain a high level of air quality.
Water Supply and Sanitation
Water supply and sanitation are also important challenges in underground cities. Because they are built beneath the surface of the earth, underground cities may have limited access to fresh water sources such as rivers, lakes, and aquifers.
To address this challenge, underground cities must be designed with advanced water treatment and distribution systems that can provide a reliable supply of clean water for drinking, cooking, and sanitation. This can include the use of desalination plants, water recycling systems, and underground storage tanks.
Psychological Impact
Living underground can also have a psychological impact on residents, particularly those who are used to living above ground. The lack of natural light, limited access to outdoor spaces, and the feeling of being enclosed can lead to feelings of claustrophobia, anxiety, and depression.
To address this challenge, underground cities must be designed with features that promote mental health and well-being, such as artificial lighting that mimics natural daylight, green spaces and gardens, and common areas for social interaction.
Examples of Underground Cities
Derinkuyu, Turkey
Derinkuyu is an ancient underground city in Turkey that dates back to the 7th or 8th century BCE. The city was built by the Phrygians, an ancient Indo-European people, and could house up to 20,000 people. It features a complex network of tunnels, chambers, and ventilation shafts, as well as amenities such as churches, stables, and storage rooms.
Orvieto Underground, Italy
The Orvieto Underground is an underground city in Italy that was built by the Etruscans in the 6th century BCE. The city was constructed beneath the hill town of Orvieto and features a network of caves, tunnels, and wells that were used for storage, defence and water supply.
Lalibela, Ethiopia
Lalibela is an underground city in Ethiopia that was constructed in the 12th century as a "New Jerusalem" after the Muslim conquest of the Holy Land. The city features 11 rock-hewn churches that were carved out of solid volcanic rock and connected by a network of tunnels and passageways.
Mary King's Close, Scotland
Mary King's Close is an underground city in Edinburgh, Scotland that was built in the 16th century and served as a refuge during the plague epidemics of the 17th century. The city was built beneath the streets of Edinburgh and consisted of a network of narrow alleyways, tenement buildings, and storage vaults.
Underground City of Montreal, Canada
The Underground City of Montreal is a modern underground city in Canada that was built in the 1960s as a way to connect the city's downtown buildings and provide shelter during harsh winters. The city features a network of tunnels and chambers that span over 32 kilometres and include shops, restaurants, museums, and even a hockey arena.
Future of Underground Cities
Urban Planning and Development
As cities continue to grow and expand, the concept of underground cities is becoming increasingly relevant in urban planning and development. By building downward instead of outward, cities can create additional living and working spaces without the need for land acquisition or the displacement of existing communities.
In addition, underground cities can be designed to be highly efficient in their use of space and resources, with compact living quarters, shared amenities, and advanced infrastructure systems. This can help to reduce the overall footprint of the city and minimize the impact on the surrounding environment.
Sustainability and Resilience
Underground cities can also play a key role in promoting sustainability and resilience in urban areas. By providing protection from natural disasters, extreme weather, and other environmental hazards, underground cities can help to ensure the safety and well-being of residents.
In addition, underground cities can be designed to be highly energy-efficient, with advanced heating and cooling systems, renewable energy sources, and water conservation measures. This can help to reduce the environmental impact of urban living and promote long-term sustainability.
Innovation and Technology
The development of underground cities also presents opportunities for innovation and technological advancement. From advanced construction techniques and materials to smart infrastructure systems and sustainable design, underground cities can serve as testing grounds for new ideas and technologies.
In addition, underground cities can provide unique opportunities for research and education, with underground labs, classrooms, and museums that allow for the study of geology, archaeology, and other related fields.
Social and Cultural Impact
Finally, the development of underground cities can have significant social and cultural impacts on urban communities. By providing affordable housing options, shared amenities, and public spaces, underground cities can help to promote social cohesion and community building.
In addition, underground cities can serve as cultural and artistic hubs, with underground galleries, theatres and performance spaces that showcase local talent and creativity.
Conclusion
Underground cities have a long and fascinating history, dating back to ancient times when they were used for defense, shelter, and religious purposes. Today, underground cities are being developed for a variety of reasons, including space savings, energy efficiency, and protection from natural disasters and extreme weather.
While there are certainly challenges to building and living in underground cities, such as structural integrity, ventilation, and psychological impact, there are also many potential benefits. From promoting sustainability and resilience to providing opportunities for innovation and cultural expression, underground cities have the potential to transform the way we live and work in urban areas.
As cities continue to grow and evolve, we will likely see more and more examples of underground cities being developed around the world. Whether as a solution to the challenges of urbanization and overpopulation or as a way to promote sustainability and resilience, underground cities represent an exciting and innovative approach to urban living.