One of Antoni Gaudí's least-visited works, an homage to Catalan patrimony that mixes neo-Gothic with Modernista forms.

A cemetery in Barcelona's Poblenou district is home to this touching funerary statue, which depicts death in the form of a winged skeleton.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

This cemetery features modernist statues as strange as its name.

A beautiful but toxic fountain of mercury.

A geological wonder shrouded in myth.

A hundred copies of Antony Gormley's naked body stare out across the water.

After mysteriously refusing to surrender at the end of World War II this sunken submarine was only salvaged in a search for Nazi gold.

This pagoda was once the central feature of a Buddhist temple that no longer exists.

Only a few pieces remain of the structure that carried people and goods across the Thames for some 600 years.

This South London cemetery holds the remains of more than 15,000 people.

The world's largest collection of ship figureheads includes figures from legends and history alike, from Sir Lancelot to Abraham Lincoln.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Graffiti from the 16th and 17th centuries cover the walls of this part of the Tower of London.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

The ritual has been performed uninterrupted for nearly 700 years.

Before becoming a poet John Keats studied here to become a surgeon.

The first tunnel to be dug beneath a river, repurposed as an art and museum space.

The verdant mossy ruins of a Franciscan monastery lie in the remote Sintra hills awaiting exploration.

Ring the bell to enter a bar that looks equal parts museum and old curiosity shop.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

An automaton perched above an classic clock and watch store

Sometimes called the Banksy of Madrid, Muelle was a pioneer of street art in the Spanish city.

Remains of the lost church hide beneath this Spanish Parliament building.