A tiny Greek Orthodox church from the Ottoman era hides on a busy city street.

After a catastrophic forest fire, a Greek artist transformed scorched tree trunks outside an old sanatorium into this haunting sculpture garden.

The ruins of an ancient mansion sits in front of and underneath a contemporary art gallery.

The site where hundreds of Greeks were tortured by the Nazi secret police is now a cosmetics store.

Scars of this building's past life as a violent prison still cover its walls.

A man's head is enshrined beneath a statue near the first building constructed for the modern Olympic Games.

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.

This gem is often wrongly overshadowed by the larger, newer Metropolis church in Athens.

Where commuters walk through remnants of an ancient Greek necropolis.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

The ruins of an ancient Roman tomb hidden in the basement of a trendy clothing store.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

A sharp sculpture made of thousands of pieces of jagged glass.

Legend says this sacred tree was a gift from goddess Athena.

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

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

This ancient hydrological marvel is now the base of a modern outdoor cinema.

The Cycladic architecture makes this Athens neighborhood feel like an island paradise hidden in the shadow of the Acropolis.

The railway carts travelers to central Athens's highest peak, which offers stunning vistas of the city.

Atop this library is one of the most beautiful green spaces in Warsaw.

These plaques found across Warsaw commemorate the sites where executions or battles took place during the German occupation.

An artificial date palm stands as a memorial to Warsaw's Jewish community.

Hundreds of notes give thanks to the patron saint of lost causes.