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

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

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

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

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

These medieval skyscrapers dominate the skyline of this small Tuscan town.

In a city that boasts four separate inclined cable railways, this is one of the busiest funicular lines in the world.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

Pilgrimage site for star-crossed lovers.

More than 5,000 artifacts donated by the people of the city, plus a room entirely devoted to the band U2.

The modern birthplace of Irish freedom.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Medicinal spa created with the discharge from a geothermal energy plant.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

Museum dedicated to the terror regimes of Hungary.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A vast Communist-era exhibition space in the Bulgarian capital.

A collection of art from Bulgaria's time as a communist state.

A striking symbol of the Bulgarian capital.

This historic black and white monastery is one of Bulgaria's architectural jewels.

An abandoned saucer-shaped monument in the Bulgarian mountains.