This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

The narrowest street in Paris.

The celebrated eyesore created by starry-eyed sweethearts.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

The first green space constructed on an elevated viaduct.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

This Roman statue is missing a limb from when the Venetians stole it from Constantinople during the Crusades.

Go inside to really appreciate this 500-year-old technological masterpiece.

Two stone columns flank the grand Venice square, but there were supposed to be three.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

According to tradition this is the oldest church in Venice, but its actual age is a mystery.

A new sculpture calls attention to climate change in the centuries-old city it threatens.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

Thousand-year-old Viking runes adorn an ancient Greek lion at the entrance to the Venetian Arsenal.

A bright little alley in La Boca is a part of tango history.

The narrowest house in Buenos Aires is less than 10 feet wide.

These small sculptures pay homage to the lovable star of an iconic Argentine comic strip.

A tower devoted to — and modeled after — the Divine Comedy.

This historic, palatial theater is now one of the world’s most beautiful bookstores.

Buenos Aires' city of the dead contains some very famous remains, including Eva Perón.

105-foot wide giant metallic flower blooms anew every day in the heart of Buenos Aires.

With its vast selection of books, comics, and records, this nearly 70-year-old open-air market always rewards the patient browser.

Spanish religion mixed with local architecture has yielded a network of churches unlike any other.