Italy's curious field of mud volcanoes is named for being both gross AND salty.

A stunning bridge that appears as if it's lunging to the shore, and has a legend of a devilish architect.

Renaissance villa and gardens complete with a tormented colossus.

The only visible reminders of an elaborate engineering project that kept the tower from reaching the tipping point.

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

Where Venice's gondolas go for a tune-up.

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

Some say this medieval church is where the poet Dante married his wife and also met the love of his life.

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

Pompeii's less famous neighbor is still revealing her secrets.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

Experience architect Le Corbusier's modernist design for living in the home he designed for himself.

A lumberjack in Finnish Lapland did not want to cut down his Arctic pines, so he offered them up to be adopted by nature-lovers.

From the sky, a kaleidoscope of color brightens the grey landscape of the San Francisco Bay.

Thanks to a spelling mistake this bizarre beaver-tiger hybrid became the symbol of a Siberian town.

Extraordinary animals sculpted from leftover junk.

Bridge that died in war and was resurected.

A hidden art gallery in an abandoned Warsaw fort.

Eduardo Kobra’s breathtaking 32,300-square-foot graffiti wall took over Rio’s Olympic Boulevard.

The secret medieval communication system will whisk your words above the noise of the crowd.