A black cat protests the City Guild in Riga's Old Town.

The summer residence of a Spanish ambassador who brought viticulture to an impoverished region, sparking its transformation into one of the world's best wine regions.

A relic from the Industrial Revolution got a second life as a contemporary performing arts space.

Martin Bricelj Baraga's monolithic sculpture measures the blueness of the sky, and changes color to match it.

The mile-long pier stretches from a ruined fortress out into the Baltic.

Medical museum that houses most notably the taxidermied remains of Vladimir Demikhov's famous two-headed dog experiment.

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

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

The curious underground history of keeping Paris clean.

The only microgravity tower in Europe can produce nine seconds of weightlessness.

Model Trains and Much More in Hamburg.

Home to 10,000 medical specimens including the remains of Rudolf Virchow's extensive collection of pathological specimens.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

The mark of the Devil's horns on a marble column in Milan.

Before there were doorbells this bronze ear was installed for visitors to announce their arrival.

Two very green residential towers cleaning the air in one of Europe's most polluted cities.

One of the world’s smallest bars, just 13 square feet, is brimming with speakeasy flair.