This World War II-era bunker hides between medieval chapels in Nijmegen's city center.

Organisms normally seen under a microscope decorate this church.

The largest airborne operation in history was launched to capture this bridge.

A German apartment building hosting as many trees as human occupants.

The last Tsar of Russia constructed this private church just so he could attend services when visiting his wife's hometown.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

This enormous "cloth of the conquest" depicts the Norman invasion of England in mind-blowing detail.

Remains of the artificial harbours invented for the Allied invasion of Normandy can still be seen at sea.

This cathedral hides a sculpted dog that determines your fate and an unexploded shell from World War II.

Once home to one of the oldest banks in the world, this building is also where Marco Polo's famous travelogue was written.

This statue of the great Argentinian car driver is located near a famous curve of the Monaco Grand Prix.

A thought-provoking outdoor art installation sits in the seat of German law.

A man throwing a giant severed hand towers over Antwerp’s main square.

This former guildhall with a bacon-like exterior is now home to a museum covering 600 years of Antwerp's musical history.

This legendary giant, born from vegetables, terrorized townspeople and cheated local children in games.

This tri-part waterfall is a little bit of fairytale beauty in the heart of Luxembourg's Little Switzerland.

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

In a city that boasts four separate inclined cable railways, this is one of the busiest funicular lines in the world.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Erotic art covers the walls of the largest ancient pleasure palace.

Before it was buried by volcanic ash, this fast-food restaurant fed the hungry hordes of ancient Rome.

Ancient snack bar of the Roman Empire re-opened.

Pompeii's less famous neighbor is still revealing her secrets.