This massive mural by famed pop-artist Keith Haring was hidden for almost 30 years until its 2018 rediscovery.

The gargoyles and grotesques of the 21st century are here—22 emoji built into a new building in the Netherlands.

Lombardy poplars planted to imitate the size and shape of the Cathedral of Notre-Dame de Reims.

A roadway designed for a visiting monarch.

An awe-inspiring giant blue whale jaw bone stands in the center of this Dutch island.

The highest cold-water geyser in the world.

The former headquarters of history's oldest megacorporation.

Hidden within a Netherlands crater is a stone bed that lets those who lie in it see the sky as a curved surface.

It's forbidden to dig within this ancient Roman fort hidden beneath a playground.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

The world's only museum devoted to the wonders of fluorescence.

The UK's oldest theme park slowly slips away.

This lighthouse was crafted as penitence for the theft of wine bound for a monastery.

These steps offer a breathtaking view of one of Europe's most besieged fortresses.

Next to the Leaning Tower of Pisa is a cemetery home to ancient sarcophagi and disturbing murals.

The ruins of this Dutch castle sit atop a labyrinth of once-secret tunnels and passageways, dating back over 900 years.

The location of a citizen uprising that led to a gruesome act of mob justice.

An amusement park on the grounds of an unused nuclear power plant, with a swing ride inside the cooling tower.

This mine was once used to defend the coast from attack during World War II.

This vast World War II defense line was the site of a fierce battle.

Inside this cathedral is a shoulder bone belonging to the Patron Saint of Scotland.

This tower once belonged to a castle fit for a knight.

The body of at least one victim of a construction accident was left behind in the collapsed pylon, buried under tons of concrete.

Largest illuminated advertisement sign in the world.