A 90-year-old underground water reservoir offers a more industrial kind of tranquility.

A castle built for love, and abandoned due to heartbreak.

This tiny little island has, as the name says, just enough room for its single house.

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

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

Experience what life was like in Ireland during the Viking and medieval ages.

The somber sculptures commemorating Irish Famine on the river Liffey in Dublin.

An abandoned piece of phallic art repurposed by locals into a makeshift fertility shrine.

Europe’s oldest natural human mummy.

Inspired by the more famous Scrovegni Chapel, Cappella di San Giovanni contains several amazing frescoes.

The first passenger cable car in the world.

Former villa and estate of James Deering developed to preserve native tropical forests.

This colorful but controversial ceiling has been likened to a 21st-century Sistine Chapel.

Baroque celebration of the end of the Great Plague of Vienna.

Finland's oldest astronomical observatory once played a crucial role in seafaring and timekeeping.

Legend says if you stick your thumb in the hole and it gets wet your wish will be granted.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

A peculiarly shaped brass sculpture hidden in a courtyard in central Lviv

Elaborate mansions built by Roma residents in Soroca to show their success after centuries of discrimination.