A fantastical 13th-century fortification sandwiched by a modern hotel in central Brussels.

In an area where the remnants of WWI are discovered on a regular basis this preserved frontline trench may be the most amazing.

The site where one of the most famous poems of World War I was composed is preserved to honor the legacy of the work.

A rare example of World War I trenches from the British front.

Medical history with an amazing, if frighting, collection of wax diseases on display.

A Belgian self-built tower inspired by the Bible and ancient civilizations.

A magical and peaceful ruined Cistercian abbey in what is now southern Belgium.

An Austrian house of bones filled with hundreds of intricately painted skulls.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

This skeleton-filled altar piece served as a backdrop to one of the most iconic scenes in "The Sound of Music."

This one-time health resort was used by aristocrats around the world.

The medieval network of canals hidden underneath the city is opened to explorers each year.

Terrifically morbid cemetary and site of famous Paracelsus' grave.

This museum promotes informed contraception by documenting its often secret past.

This little medieval church hidden in the center of Yerevan was lost and rediscovered—twice.

Hundreds of intricately carved Armenian stone crosses can be found within this huge cemetery.

The ruins of a medieval monastery built on a perilous slope.

The world's longest nonstop reversible cable car soars through spectacular scenery to the medieval Tatev Monastery.

Centuries before the modern seismograph, Armenian monks measured quakes with this tilting pillar.

The most visited pilgrimage site in Armenia once held a saint in a pit for 13 years.

This Armenian monastery was carved out of cliffs and named after the spear used to stab Jesus.

This series of Armenian caves held the oldest brain, shoe, and winery in the world.