The site of the first battle of World War II.

This Nazi ruin was the site where Hitler was almost blown up by a suitcase bomb.

This grubby wall is said to be one of the Earth's esoteric energy centers.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

This extensive collection covers thousands of years of Polish military history.

Tourists often confuse this beautifully ornate former cigarette factory for a mosque.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

This wrecked airplane has been sitting on a black sand beach since the 1970s.

Along this wire fence, travelers have been leaving a particular memento since 2012.

An underground city of salt.

This outdoor library provides around-the-clock access to around 7,000 books.

This old wooden funicular railway leads to a cemetery in the forest.

Cairns built to bring travelers good luck stretch across the land like miniature stone mountains.

Instead of solid circles, the stoplights in this northern Icelandic town have glowing red hearts.

Medicinal spa created with the discharge from a geothermal energy plant.

France's most famous cemetery, with some of its most curious tombs.

An artificial date palm stands as a memorial to Warsaw's Jewish community.

The Polish capital has had a deep connection to its guardian mermaid for almost a millennium now.

The giant statue and its model solar system honor the native Pole who declared that the Earth revolves around the Sun.

The 14th-century ruins are said to contain healing powers.

An enormous and lavish Gothic church in Czechia.

The biblical sculpture honors those who lost their lives, homes and communities to the Chernobyl disaster.

Real bones which are said to have belonged to a Polish dragon.