Thousands of coffin-like pillars make up this controversial Holocaust memorial.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

The most visited, and possibly most controversial, museum in Germany.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

One of Amsterdam's narrowest houses is located right across the canal from its widest.

Amsterdam's former hotspot for public executions and dissections.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

Ordinary art transforms to extraordinary thanks to locals' quirky sense of humor.

This bridge was constructed from the rubble of the infamous Bastille.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

Historic medieval fortified city in southwest France.

This salt marsh in Southern France is as pink as the flamingos that inhabit it.

A 14th century bridge built as a fortress, where the devil lurks on one of its towers.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

Ancient paintings known as the "Sistine Chapel of Cave Art."

The first green space constructed on an elevated viaduct.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.