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

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.

This tile-work piece featuring a chicken riding in carriage is both a remarkable artistic creation and a social commentary of politics and culture in 17th-century Portugal.

The famous polar explorer stands outside the Royal Geographical Society's headquarters.

A network of bells in the pubs and restaurants around Westminster alerts politicians when it's time to cast their votes.

This may be the last of London's wooden pavements, which were once a common sight in the city.

England's most famous front door has an accidental doppelganger.

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

The first geometric self-supporting spiral stairs in Britain are a truly beautiful sight.

This unique bridge curls up like a caterpillar to let boats pass and then unfurls again to span a small canal.

A Roman spa buried deep beneath the City of London.

Claiming to be the oldest hat store in the world, this historic haberdashery had a hand (and a head) in the creation of the Bowler.

A statue marks the exact spot where The Boy Who Never Grows Up made his first literary appearance.

A network of concealed passageways lies within a busy London Underground station.

A historic London pub with prison cells in the cellar and a "spy room" on the second floor.

The world's first underground farm is in a World War II bomb shelter beneath the streets of London.

These lights mark the area of Rotterdam that was bombed and burned in 1940.

Some 80,000 Delft Blue tiles line the inside of this Amsterdam walkway.

The world's largest bicycle shelter can hold more than 12,500 two-wheelers.

This small museum located under the famous cube houses, is home to some 30,000 chess pieces.

In the Netherlands, one of the world's largest private car collections can be found.

A set of seven houses, each built in a style that represents a European country.

Built by crowdsourcing, this wooden foot bridge saved a part of Rotterdam that was languishing in wait of city funding.