340-foot statue built to honour the Heroes of the Soviet Union.

The deepest metro station in the world.

This hill is known for its connection to the occult in Slavic tradition.

Longest road tunnel in the world features an air treatment plant and the illusion of daylight.

This floating sculpture of ice is a poignant reminder of nature's power.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

The fishing boats that moor in this small lagoon enter and leave through a tunnel to the sea.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

This 50-foot-deep sinkhole created in the 14th century is home to rare plants and fungi.

This daunting 1st century fortress was purportedly the site of one of the most dramatic revolts of the Jewish-Roman wars.

The most alien-looking place on Earth.

A 900-year-old village located in the highland of the Asir region that features historic architecture.

A man has revenged his true love's betrayal through tears and stone genitalia.

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

A wooden street sign is the last remnant of this 400-year-old alleyway.

A plaque marks the house in Stockholm where the French philosopher René Descartes lived up until his death.

Stockholm's tiniest statue is of a small boy looking at the Moon.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

Several cannonballs of mysterious origins decorate two buildings in Stortoget's main square.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

This charming Latvian lane doubled as Baker Street on the Soviet Union’s version of Sherlock Holmes.

A preserved oak tree about 3,500 years old found in Riga, Latvia.

The reconstruction of this prominent building fulfilled a long-written command.

3,000 market stands in five former Zeppelin hangars.