Two standing giants remain as a tribute to Luxembourg's metallurgical past.

The people of Padua pledged to construct this church if the city was spared from destruction during World War I.

This massive monument honors the first human in space.

Its interior is adorned with some of the best examples of early Christian mosaics.

The city walls of Salé lead to the ruins of this seaside "bastion of tears."

Drink among marionettes at this pub inside a historic puppet theater.

This once-controversial and slightly confusing statue of Achilles was built out of captured cannons.

Claude Monet was baptized in this lavishly ornate Paris church.

Climb a steep hill in 90 seconds on the second-oldest urban subway in the world.

Mysterious heaps of stones dot these otherworldly woods.

An ornate private entrance to the Vienna subway built specifically for the emperor.

This magnificent Art Deco church is a reflection of Lithuania’s turbulent history.

Plaques celebrating Lithuanian writers freckle a wall of this picture-perfect path.

Where a Japanese government official issued transit visas to Jews fleeing from Nazi-occupied Poland.

For the last century, this international border within a small town has appeared and disappeared various times.

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

A statue of the Soviet leader still stands in a quiet corner of Estonia’s most Russian city.

An abandoned masterpiece of Soviet Brutalist architecture.

This ornate church has survived Nazi and Soviet occupation, including a short stint as a Soviet-era gymnasium and cinema.

This ancient Roman arch misled treasure hunters for centuries.

The pockmarks across the building's facade are remnants of the Blitz.

This recessed garden protects thousands of mountain plants by creating its own microclimates.

The rocks are a time capsule of a 407-million-year-old Earth.

This structure atop a craggy cliff in one of the most beautiful parks in Paris boasts an unbeatable view.