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

Luminaries of all stripes have sipped strong Greek coffee at this cafe since 1839.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

This church was constructed on the site where St. Philip the Apostle preached to the ancient Athenians.

Catch raucous live performances of traditional tunes at this old-school taverna.

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.

With no menu and no sign, this 130-year-old taverna doles out affordable home cooking.

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

This Ottoman-era Greek Orthodox Church was built to honor Agia Pareskevi, a Christian saint.

An ancient site that has revealed incredible artifacts including portions of the Themistoclean Wall.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

A mechanical clock built in 1914, with a rotation of 12 historical figures on its face.

This museum is dedicated to the little known ancient Roman history of Vienna.

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

A monument dedicated to a lone, brave invader.

Museum devoted to the artificial language of Esperanto.

Handsomely crafted representations of our round planet.

In the middle of a Vienna square, Roman ruins dating back some 2,000 years are on display.

The beautiful baroque library of the Hapsburg empire.

Designed as a reminder of one of the darkest moments in Austrian history.

The townhouse where the "Blood Countess" Elizabeth Báthory started her murderous career.

The final resting place for the remains of 143 Habsburg royalty.

Legends surround an ancient tree trunk riddled with nails for good luck.

These two 15th-century metal rods allowed people to check if they were swindled or not.