The celebrated eyesore created by starry-eyed sweethearts.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

Museum on French naval history, with magnificent figureheads, a historic diving suit, and a boat used by Napoleon.

A modern-day Lascaux cave underneath Paris.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

The curious underground history of keeping Paris clean.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

This Parisian fountain is a little bit fantasy and a little bit nightclub.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

"In the Dark" Restaurant in Paris offers dinner in complete darkness.

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

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

A rooftop restaurant hides in plain sight atop Vienna's Palace of Justice.

Apartment complexes built into huge repurposed natural gas tanks.

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

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Red frames showcase remnants of one of New York's original subway stations.

The most confusing clock in New York.

This exemplar of modernist architecture is meant to captivate and inspire students of the Cooper Union.

This elaborate tunnel is the first structure composed of cast concrete in the United States.

This secluded ruin was once a home for exotic plants.

A bronze statue of the famed Prussian naturalist commemorates the year he spent in Mexico.

Gilded heaven for philatelists and architecture freaks, still in full working order despite sitting atop tremulous ground.

CDMX's home for the world's culinary delights.