The last moments of the ill-fated Pompeiians, frozen forever in plaster.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

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

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

The Habsburgs' royal collections of art and wonders.

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

Baroque celebration of the end of the Great Plague of Vienna.

The topiary maze at the Habsburg hunting lodge.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

A public work of art that also provides some relief from the summer heat.

A whimsical bridge adorned with decorative dragons.

This one-time health resort was used by aristocrats around the world.

This 2,000-year-old Doric bridge is still open to pedestrian traffic to this day.

The smaller of the three towers of San Marino is a former prison inaccessible from the ground level.

This picturesque horseshoe weir was first built in the 1600s to prevent flooding in the town of Bath.

Scattered throughout London are ancient remnants of the city's former bounding wall.

A memorial for public executions that dates back to the 14th century.

A mysterious pair of mice eating a piece of cheese is London's smallest public sculpture.

The Great Fire of London and the regulation of one-way streets both started in this alley.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

Once the fallout shelter of a dictator, this sprawling bunker is now a combined history museum and contemporary art gallery.