Top 10 Most Fascinating Underground Cities

Located in Cappadoccia, Turkey, Derinkuyu is an ancient underground city that stretches over 18 kilometers of tunnels and chambers. Built around 800 BCE by the Phrygians, it was expanded upon by the Hellenistic period and served as a refuge for thousands of people during times of war and persecution. The complex features over 20 entrances, with only three discovered so far. Derinkuyu is believed to have housed up to 20,000 inhabitants during its peak. The underground city's architecture and infrastructure were designed to support the needs of its residents, including a sophisticated ventilation system and a network of water supply systems.

Situated in Denizli, Turkey, Pamukkale is an ancient city built into the sides of hot springs and travertine formations. Excavated around 500 BCE by the Phrygians, it features numerous underground tunnels and chambers that were used for various purposes, including storage and worship. The complex contains several impressive frescoes and artifacts, providing valuable insights into ancient Turkish culture. Pamukkale is home to over 1,000 ancient ruins, showcasing the city's rich history and architectural achievements. Despite being largely forgotten in recent centuries, Pamukkale remains an important archaeological site.

The nearby underground city of Kaymakli was also built during the Hellenistic period, around 500 BCE by the Phrygians. This labyrinthine network stretches over 4 kilometers and features several entrances, including a hidden entrance beneath a monastery. The complex contains extensive frescoes and artifacts from ancient Turkish culture. While less explored than Derinkuyu, Kaymakli provides unique insights into life in underground cities of ancient Turkey. Today, the site is open to visitors for guided tours.

Located in modern-day Iran, the underground city of Kish dates back to around 1500 BCE and features an impressive network of tunnels and chambers carved into volcanic rock. This ancient city was home to over 200,000 inhabitants during its peak and served as a strategic military outpost. The complex's unique geology played a crucial role in its construction, providing natural protection against invaders.

In the Altai Mountains of modern-day Russia, lies an extensive underground city that dates back to around 320 BCE. This massive network stretches over 1 kilometer and features several impressive structures built into the side of a cliff. The complex's architecture showcases advanced knowledge of stoneworking and engineering for its time.

Also in modern-day Georgia, this underground city was carved from volcanic rock around 1200 BCE and stretches over 3 kilometers. The ancient structure features an impressive series of tunnels, caverns, and towers built into the mountain's surface. Little is known about the city's history or its former inhabitants.

Also known as Yenikale, this nearby underground city in Turkey was also built during the Hellenistic period. It features an impressive labyrinthine network that stretches over 3 kilometers and includes multiple entrances and a sophisticated water supply system.

Located in modern-day Turkey, this ancient underground city dates back to around 700 BCE. Built by the Phrygians, it stretches over 2 kilometers and features several impressive structures built into volcanic rock.

In northern Iran, lies an extensive underground complex that was unearthed in the 19th century. Dating back around 2000 BCE, this network of tunnels and chambers is thought to have been occupied by various ancient civilizations over time.

Situated in central Australia, this underground community was initially established as an opal mining town in the late 19th century. Today, it features a complex network of tunnels and caverns containing homes, shops, and services for residents, as well as extensive infrastructure for maintaining their unique environment.