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.

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.