Hidden Beneath the Cities

Uncover a vast underground city in Turkey that served as a refuge for Christians and Jews. Investigate a mysterious chalk chamber in England, visit a secret Etruscan complex beneath an Italian wine cellar, and map an ancient tunnel network in Iran.

Marvel at the crystal caves and underground chapels of Poland's Wieliczka salt mine. Tour a secret Cold War bunker in England, unearth a 3,400-year-old royal settlement in Egypt, and try to solve the mystery of China's enigmatic Longyou Caves.

Investigate a tomb in Naples that may contain a prince who inspired the legend of Dracula. Read the desperate letters of Jewish rebels hidden in an Israeli cave, tour a 6,000-year-old labyrinth in Malta, and see the oldest human burial in Africa.

Crawl through a notorious brick-lined tunnel system in a historic Florida neighborhood. Open a window into the lives of elite Greek families in Naples, explore a three-story underground city in Iran, and find 2nd-century barracks buried in Rome.

Explore a labyrinth built beneath Washington, D.C., by an eccentric entomologist. Admire a fresco-filled Roman mausoleum, spot intricate chambers carved into Colombia's volcanic rock, and see a sprawling network of hand-dug tunnels in Liverpool.

Explorers find a tunnel system, mass graves, city foundations, and longhouses.