This historic Amsterdam bar used to accept sailor's monkeys as payment.

The attic of a four-century-old canal house hides a clandestine church.

A beautiful maze marks where three countries meet.

This small town in the Netherlands has no roads but instead, miles of canals and over 100 bridges.

Peek through a transparent pyramid and drink in the mountain made of books.

A centuries-old forgotten underworld lies beneath Malta.

The fishing boats that moor in this small lagoon enter and leave through a tunnel to the sea.

Abandoned Roman Catholic chapel abused by Satanists before being restored.

This almost-forgotten underground dungeon housed several convicts over the years, including Caravaggio.

This unique building in the main square stands out among the city's typically Baroque architecture.

The ruins of a megalithic monument sit right in the garden of a luxurious Maltese resort.

Enigmatic tombs and cave dwellings on the outskirts of a rural village.

Overshadowed by other, more famous Maltese catacombs, this ancient burial chamber has one of the best examples of a ritual agape table.

These lesser-known Maltese catacombs date back over 1,700 years.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."

This prison on the Maltese island of Gozo is almost 500 years old, and they have the graffiti to prove it.

The remains of a 1st-century aristocratic Roman town house featuring beautiful well-preserved mosaics.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

This subterranean necropolis holds three floors of antler-dug grave caves.

This Stone Age solar temple aligns with the sun on each equinox and solstice.

The tomb of the mythological founder of Padua is not hidden in some obscure crypt, but stands right in the middle of the city square.

Something's missing between the arcades of the Palazzo della Ragione in "the city of the three withouts."

Once an ancient Roman bath, now a hotbed of geothermal energy and a hub for energetic innovations.

A mysterious ancient elephant said to possess magic powers is now the symbol of a Sicilian city.