Atop this library is one of the most beautiful green spaces in Warsaw.

A renowned Civil War veteran, this Bald eagle now presides over the Wisconsin State Assembly.

Former self-sufficient mental institution now a planned community.

A subterranean world of tunnels links several buildings of this rare 19th-century asylum.

This freshwater spring fills with 10,000 gallons of water per minute.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

One Portuguese poet described this cape, the westernmost point in mainland Europe, as "where the land ends and the sea begins."

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

The medieval castle built as headquarters for the Pope's secretive Knights Templar.

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

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

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

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

This charming candle shop has been in business since 1789.

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

The world's oldest bookshop still in operation.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

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

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

The last king of Poland was interred in this church nearly 200 years after his death.

In the summer, the area around this sculpture transforms into a vibrant concert venue.

This enormous 32-foot painting depicts Poland's greatest medieval battle in glorious detail.

A hidden art gallery in an abandoned Warsaw fort.

This hidden collection of everyday objects illustrates life within communist Poland.