Where commuters walk through remnants of an ancient Greek necropolis.

A mocking tribute to the past and modern leadership of Prague.

The Slovenian architect designed many landmarks in the capital city, including his own dream house.

17th century palace once a meeting place for politicians.

Hidden in a grotto 26 feet below Nottingham's oldest hotel, this stylish subterranean drinking den is notoriously hard to find.

There's a labyrinth of medieval chambers hidden deep below a 15th-century pub.

The most gigantic, swoony, intimidating trio of fingers in all of antiquity.

England's steepest street has such a drastic incline that locals tie their parked cars to lampposts when it gets icy.

This unassuming oasis elevated just above the busy streets of Jerusalem offers one of the best views of the Old City.

The home of the Dead Sea Scrolls is an abstract modernist dream.

An ancient tunnel in Jerusalem built to redirect water in the event of a siege is one of history’s great architectural innovations.

This "Jewish Sistine Chapel" was designed to reinvigorate Judaism's artistic legacy but was almost lost to misguided restoration.

A plaque marks the house in Stockholm where the French philosopher René Descartes lived up until his death.

Although rarely used, there is still a hidden room for the royal family at the Stockholm central station.

A hidden bathhouse in one of Stockholm's oldest and busiest neighborhoods is open to anyone who can find it.

The library's graceful rotunda is like a bibliophile's temple.

The Swedish flag over this small naval fort signals that the nation is at peace.

The remains of Alfred Nobel's first nitroglycerine factory can still be found on the shores of a Swedish bay.

It houses the remains of a 17th-century version of the Titanic.

This spaceship sculpture in the middle of the Slovakian capital looks like it just crash-landed.

This townhouse was once the original home of the Scottish Football Association.

Inside this art museum resides one of Glasgow's most famous musical instruments.

The old tradition of drying laundry on poles in the public green is still guaranteed by Glasgow city law.

"Respectful to the dead, safe and sanitary to the living, dedicated to the Genius of Memory..."