This abandoned shopping arcade has new life as an art installation.

The oldest standing Byzantine church in Athens is tucked within a monastery in the middle of an upscale shopping district.

A Byzantine-era church hidden in a wooded area below the Acropolis.

The ruined doorway is a portal to the building's turbulent and torturous past.

An eclectic collection of thousands of items owned by the sculptor Frederic Marès.

Occupied for six centuries by Franciscan Order nuns, this monastery is an amazing ode to Catalán Gothic architecture.

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

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

This cafe offers a curated collection of treats and tipples made by monks and nuns.

Barcelona's only remaining tram system takes riders to the Tibidabo funicular.

According to myth, Zeus himself was hidden in this cave to escape being eaten by his dad.

An ancient octagonal weather station named for the eight Greek gods of wind.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

A quirky bookstore hidden beneath a sea of whitewashed Greek villas.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

Monasteries on rock pillars, once accessible only by frayed ropes.