Beautiful antiques and obscure engineering artifacts trace the evolution of phones from rare luxuries to ubiquitous.

One of the largest barracks of the Austro-Hungarian monarchy's military is now an abandoned ruin.

Legions of Roman soldiers bathed in this ancient spa complex under a Budapest transit station.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

A collection of intricate sculptures so small they have to be seen through a microscope.

Some of the greatest minds in the history of Hungarian art and science converged in this café.

The European equivalent of the Hollywood Walk of Fame is slowly spreading over the entire city.

Located inside Hoge Veluwe National Park, this museum began as the private collection of a prominent female art collector.

It's forbidden to dig within this ancient Roman fort hidden beneath a playground.

The location of the world's first telescope demonstration.

The elegant manor house where Kaiser Wilhelm II lived in exile after World War I.

A statue of the second-tallest Dutchman in history.

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.

What happens when you cross a mayor and a painter?

Bronzes and busts that once stood in the city's main squares are now relegated to a small hidden courtyard.

Panoramic views from the mountains over a facility built to provide tuberculosis patients with fresh mountain air.

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

This fairy-tale, neo-Gothic church in the Azores is a world of magical realism.

This ancient trail climbs the mountain where a Latin League cult worshipped Jupiter, its main deity.

A collection of objects supposedly singed by the hands of souls in purgatory.

This pub was 238 years old when it decided to revamp its image: It started serving Thai food.

The world's oldest known salt mine.

During World War II, Austria's oldest salt mine was used to store thousands of pieces of stolen artwork.