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

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

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

Made of 41,900 pieces of mosaic, it took two years to piece together this giant egg.

This burial pyramid in central Ireland is thousands of miles and thousands of years away from its Egyptian inspiration.

A seaside town with no sea in sight.

This charming railway is one of the oldest and steepest funiculars in England.

A slightly surreal menagerie of structures that were lovingly spared from demolition and reconstructed in a field.

The last occupied troglodyte dwellings in England weren't abandoned until the 1960s.

This medieval manor house was equipped with secret compartments for hiding priests.

This pub can leave even the sober feeling slightly unsteady.

Stunning Roman aqueduct used for 1900 years and still standing.

The abandoned ruins of a beautiful medieval castle just outside Barcelona.

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

This house's itty bitty size means no humans allowed.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

Bacteria and algae give the salty water its bubblegum hue.

An ancient Egyptian temple in the middle of Madrid, Spain.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

A open air theatre built on a cliff by an eccentric British woman.

This crumbling folly looks like an enchanted left over from Middle Earth.

Museum about life, death, and cannibalism in the Stone Age.