Dine amidst exotic plants at this former royal greenhouse.

One of Vienna’s oldest (and perhaps most haunted) alleys, allegedly with a bloody past that gave it its name.

The townhouse where the "Blood Countess" Elizabeth Báthory started her murderous career.

The beautiful baroque library of the Hapsburg empire.

Designed as a reminder of one of the darkest moments in Austrian history.

Op-art architecture designed for happiness.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

These two 15th-century metal rods allowed people to check if they were swindled or not.

The housing complex served as an anti-fascist fortress during the Austrian Civil War.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

The world's largest wooden structure.

This tile-work piece featuring a chicken riding in carriage is both a remarkable artistic creation and a social commentary of politics and culture in 17th-century Portugal.

In the Monastery of São Vicente resides a gallery devoted to a breathtaking collection of seashells.

This unique architectural wonder is also tied to one of the 20th-century's most renowned writers.

The scorched Lisbon church that survived two earthquakes and a massive fire.

Sip cherry liqueur at a bar dating back to 1840.

These 19th-century gas tanks were remade into an apartment complex.

This iconic high-rise residential block was one of the last to be built in the Brutalist style.

This inn of the court provides a fascinating window into London’s legal and architectural history.

One of the oldest remaining Catholic churches in England is home to the hand of a 7th-century saint.

Behind one of the world's most impenetrable vaults is a massive collection of retail silver.

The ruins of a church destroyed by both the Great Fire of London and the Blitz, now turned into a peaceful garden.

One of America's founding fathers lived in this London lodging between 1757 and 1775.