An unusual round church in London with a Templar past.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

A restaurant and observation deck built in a unique broadcasting antenna.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

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

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

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

Amsterdam's former hotspot for public executions and dissections.

One of Antoni Gaudí's least-visited works, an homage to Catalan patrimony that mixes neo-Gothic with Modernista forms.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

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

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

One of the world's tallest statues is also one of its most hated.

World's largest bell sits on the grounds of the Kremlin in Moscow.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

This building holds the embalmed remains of the leader of the Bolshevik Revolution.

Dr. Strangelove-esque tours reveal the inside a bunker once reserved for Stalin himself.

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

The fifth-longest natural arch in the world, and the longest outside China.

The only natural lake in the world that drains into both the Atlantic and Pacific Oceans.