Countless stories attempt to explain Poland's mysterious J-shaped trees.

Polish luminaries and masterful folk art find sanctuary in this unique cemetery.

Traces of the thriving lake trade that once linked the Soviet Union with Mongolia.

A marvel of technology a century ago, this disused power station now offers a lovely glimpse into the industrial design of the past.

Possibly the world's largest hourglass only needs to be reset every New Year's Eve.

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

This fortress was designed to prevent a Nazi invasion but was never used.

A mysterious structure left behind on the Polish mountainside, sometimes called "Hitler's Stonehenge".

This open-air museum was originally a World War II testing ground for German missiles and rockets.

This mysterious and once-grand memorial still embodies a remarkable architectural vision.

One of the largest amphitheaters in Europe is a former Nazi gathering place that still stands today.

This statue standing near Sweden's southernmost point was based on the grandmother of a modern movie star.

This unique rock formation is quite the local celebrity, although one day it may come crashing down.

This local emblem is the oldest and largest dragon tree in the Canary Islands.

Lava stone structures possibly dating back to the 19th century may have been a stopping point for voyagers between ancient Egypt and the Mayan Civilization.

This now-defunct synthetic fuel plant was once a major cog in the Nazi war machine.

Ruins of a late 1950s Polish ski jump ramp in the middle of the city.

A stone in Wolin, Poland, marks the possible location of a legendary Viking fortress.

People in Poland have rallied to save this unnatural desert from being reclaimed by the forest.

The site of one of the largest prison escapes of World War II.

An abandoned football stadium with a tragic past.

In northeastern Poland, the ruins of a massive granary overlook the Narew River.

An abandoned Jewish sanatorium is tucked within the woods of Poland.

The world's tallest statue of a woman wields the world's tallest sword and is at risk of toppling over.