The largest of Denmark's seven mysterious round churches stands on an island in the Baltic Sea.

This remote island, home to the easternmost point in Denmark, once hosted pirates and a military fortress.

This 13th century Gothic brick castle is the largest in the world by surface area.

These massive moving sand dunes have swallowed an entire village and are still on the run.

The ruins of a 2,000-year-old Roman fishing village perched on one of the best beaches in Spain.

According to the Guanches, the aboriginal people of the Canary Islands, the king of evil lives inside this volcano.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

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

A beautiful lighthouse with as many steps as days in the year, as many windows as weeks, and as many levels as months.

This ancient stone bridge dates back to the early Middle Ages.

A fantastic castle rumored to be the birthplace of King Arthur.

Arthur, Merlin, and Guinevere are among the largest and oldest satellite dishes on the planet.

A open air theatre built on a cliff by an eccentric British woman.

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

A local museum honors the overlooked discoveries of Mary Anning, one of the first professional fossil hunters.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.

No need to strap in for a “ride” on this walkable roller coaster.

This futuristic German television spire is actually the world's largest digital clock.

This pair of unsuspecting buildings are in fact the very first modern skyscrapers in Europe.

A temporary art piece to celebrate LGBTQ Pride is now a permanent part of Stockholm's traffic landscape.

Stockholm's narrowest alley is barely over two feet wide.

This gem from the industrial age helps visitors and residents alike traverse hilly Stockholm.

Sound travels strangely in this underground whispering gallery.