Underground World

• high-speed trains, subterranean highways, 18-wheel trucks
• Extensive underground shopping and entertainment complexes like Montreal’s RESO or Singapore’s CityLink Mall.
• Warehouses of food, supplies. Underground Cargo Distribution Hubs, Logistics centers beneath cities, allowing for the movement of cargo without congesting surface streets.
• Underground (Botanical) Gardens - Some cities have experimented with creating underground botanical gardens that use artificial light and hydroponic systems to grow plants in former underground spaces.
• Greenhouses built underground to harness geothermal heat for year-round farming.
• Urban underground farms using advanced hydroponic systems to grow food, especially in areas with limited arable land.
• Seed Vaults
• Underground Water Reservoirs - Caverns or tunnels created to store fresh water for cities, offering an alternative to surface reservoirs.
• Subterranean Burial Chambers like the Paris Catacombs, were used to house the remains of millions in an organized underground cemetery.
• Museums - Helsinki, Krakow, Tokyo, have museums or art galleries located underground, often built into former bomb shelters, bunkers, abandoned underground spaces or historic caverns.
• Underground (Botanical) Gardens - Some cities have experimented with creating underground botanical gardens that use artificial light and hydroponic systems to grow plants in former underground spaces.
• Wine regions use underground wine cellars for stable temperature storage. Other industries use underground caverns and Underground Storage Facilities for cold storage of perishables.
• Ancient Burial Chambers, Cultures like the Egyptians, Mayans, and early Europeans built underground tombs and chambers for their dead, including the Valley of the Kings in Egypt.
• Underground beneath Amusement Parks. Romania (Turda Salt Mine), have converted former underground mines into amusement parks or recreational facilities, offering unique experiences like underground boating.
• Some monastic communities have retreated underground, such as the Vardzia Cave Monastery in Georgia, a medieval complex used by monks.