A lush indoor jungle fills this bustling Madrid transportation hub.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

This historic tall ship traveled 1.5 million miles around the globe, and once did duty as the mythical pirate ship in Peter Pan.

A friendly monster lurks outside the State Library Victoria.

A remarkable lifelong collection of antiques and art preserved in a historic Melbourne townhouse.

An iconic and controversial ancient Iberian funerary urn with a hauntingly penetrating gaze.

A curious little museum dedicated to the furry feline in the cat haven that is Old Town Kotor.

The attic of a four-century-old canal house hides a clandestine church.

Incredible labyrinth of man made caves.

Famed for its pie, this eatery has a hidden tunnel that allowed Catholics to secretly walk to church during the Reformation.

An abandoned train station in Munich constructed for the 1972 Olympic games.

This cheese shop also houses a museum devoted to Dutch dairy.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

The floor of this spectacular Baroque sanctuary is covered in memento mori.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

These temples are among the oldest free-standing stone buildings in the world.

One of the oldest scientific gardens in Britain, containing more than 13,302 plant species in its core collection.

Just across from the "Last Supper" painting is the famous painter's vineyard, a gift received for creating the masterpiece.

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

The odd depiction of the Virgin Mary and baby Jesus is rooted in the Catholic Church's eradication of Catharism.

An eerie, little-known Neapolitan museum filled with preserved human remains.

In a city that boasts four separate inclined cable railways, this is one of the busiest funicular lines in the world.

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

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.