The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

The Roman Emperor's lost summer home and grotto full of enormous sculptures sit along the Italian seashore.

Lady Liberty's first beacon of enlightenment is now displayed in a museum near the statue.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

Romans built the world's tallest artificial waterfall in 271 BC.

Two stone columns flank the grand Venice square, but there were supposed to be three.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

A medieval wash house where people washed clothes in a river allegedly formed by the tears of a mourning nymph.

A tilted half-timbered house from 1672 is built into a salvaged segment of a medieval wall.

Why walk on this historical site when you can zoom down instead?

The secret medieval communication system will whisk your words above the noise of the crowd.

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

Dug as a secret royal escape route, the tunnel became a wartime bomb shelter and dumping ground for vintage cars.

This picturesque horseshoe weir was first built in the 1600s to prevent flooding in the town of Bath.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

The beloved fantasy novelist is buried near a church containing a whimsical etched glass window full of Narnia favorites.

The names Lúthien and Beren can be found inscribed on the shared grave of the famous writer and his beloved wife and muse.

An Art Nouveau gem hides beneath the layers of city grime obscuring this once-magnificent building.

The soaring gondola lines form the longest aerial cable car system in the world.

Some say this medieval church is where the poet Dante married his wife and also met the love of his life.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

No one knows the meaning behind this giant sculpture of a nude woman with a fork riding a rooster in Havana.