A Turkish homeowner chasing his chickens through a hole in his basement during renovations came across an abandoned underground Turkish city that once housed 20,000 people. ... the ancient city of Elengubu, known today as Derinkuyu. Derinkuyu, burrowed more than 280 feet beneath the Central Anatolian region of Cappadocia, is the largest excavated underground city in the world and is believed to connect to more than 200 smaller, separate underground cities ... Inside the subterranean city — whose entrances connect to more than 600 private homes in the modern, surface-level region of Cappadocia — researchers found 18 levels of tunnels...