All that is left of this medieval castle is two towers, both of which now display a visible tilt.

A rare example of an octagonal Catholic church.

A complex, nine-layer maze on the grounds of a Venetian doge's playground.

Built to repay the sins of the father, this church is home to one of the most valuable works of Western art.

One of the world's oldest working clocks is curiously missing the Zodiac sign of Libra.

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

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.

The incorrupt tongue of the patron saint of lost things is venerated in this basilica.

The oldest botanical garden in the world that technically isn't the oldest.

One of the largest squares in Europe contains an entire artificial island.

An extraordinary collection of 18th century anatomical waxworks.

A stunning hermit's shrine on a steep rocky spur in Northern Italy.

A devastating landslide accidentally created this tourist hotspot.

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.

This intriguing Bronze Age artifact spent centuries hidden within a Welsh faerie hill.

A gruesome and mysterious ancient sculpture of a pagan deity from the Roman occupation of Celtic Britain.

These mysterious Viking chess pieces spent centuries hidden on a remote Scottish island.

The "lost friend” is the most famous of the six moai statues that were removed from Easter Island.

A naturally mummified 2,000-year-old man.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

The bronze uniforms commemorate the vital role of women during World War II.

The handiwork of a underdog clockmaker who solved an impossible problem for an Empire, and forever revolutionized seafaring.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

Order bagels and lox from an iconic Jewish delicatessen with nearly a century of history behind it.