You'd never know the houses at 23-24 Leinster Gardens were fakes—until you see the train tracks on the other side.

A clock designed to run with perfect accuracy for 10,000 years.

This museum inside a museum tells the story of London's timepieces.

A little sculpture with a large wardrobe.

An abused and forgotten metropolis, abandoned for centuries.

This museum is home to one of the biggest collections of printing press technology—plus a river view.

This historic streetcar system has been running since the 19th-century.

Ancient catacombs form the foundation for this Rococo orgy of a church.

Elaborate tile work in this railway station tells the story of Portugal.

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.

The stunning interior of this Gothic church is covered in ornate gold details.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

The oldest surviving wooden bridge over Rhine lets travelers cross easily from Switzerland to Liechtensten.

In one of the world's smallest countries, a royal's personal winery is open to the public.

One of the smallest bookstores on the planet.

Entire apothecaries are on display at this Lisbon museum, which explores the history of medicine.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

A unique seaside cave where Aleister Crowley faked his own death.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

A museum dedicated to one of Portugal's most celebrated writers.

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.