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

A historic building houses one of the most important archaeological institutes in Europe.

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

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

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

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

This historic structure has been used as a mosque, a barracks, a prison, a school, and a bakery.

This striking sculpture of Icarus honors Greece's fallen flyers.

Legend says it was constructed with the destroyed pillar of an ancient Greek Temple.

There are many Byzantine-era churches still standing in Athens, but this is the only one with a 2,500-year-old column rising through its roof.

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

A crushed gate and giant bronze head serve as a reminder of Greece's fight for freedom.

An important example of architectural history slowly decays in the city center.

Captain America, Sub-Mariner, and the Human Torch were all born in this art deco Manhattan masterpiece.

An homage to Jackie Gleason's bus-driving character from 'The Honeymooners.'

Cheap pizza and all of your naughty bedroom needs housed in a stunning example of Art Nouveau architecture.

This semi-hidden Manhattan restaurant is based out of a loading dock.

The 28-foot granite map plots the locations of 40 theaters in New York City.

Amid the marketing blitz of modern Times Square is an elegant holdover from its showbiz glory days.

There must be a pun in this haystack somewhere...

A commemorative plaque hides a door that leads down to the New York Public Library's underground book bunker.

Commemorating the spot where the famous scientist fed his pigeons.

This study room in the New York Public Library saw the creation of one of contemporary America's greatest traitors.

The former home of the reclusive "Weird Wendels" who dominated New York real estate a century before Donald Trump.