A Nesting Doll of Churches.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

Breathtaking and huge 430 year old maps of Italy.

Giant acorn-shaped 19th century gazebo from which suburban Washingtonians gazed upon the original "silver" spring.

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

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

Where commuters walk through remnants of an ancient Greek necropolis.

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

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

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

A preserved portion of an ancient Athens barrier is displayed in a hotel basement.

According to legend, this ancient column contains healing properties.

The ruins of an ancient fortification wall sit in front of and underneath this boutique hotel.

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

View the ancient remains of buildings and the ancient "River of Hades" before hopping on a train.

One of the three perfect vellum copies of this historic book known to exist is on display in a specially-designed case.

This miniature village stays behind in the Breuer Building, even as the museums around it come and go.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

The famous abolitionist’s preserved estate is one of Washington's finest monuments to its great Black citizens.

A super-sized promotional trick that is now a D.C. landmark.

This weeping, 10-foot-tall sculpture was a maquette for a 9/11 memorial.

This local gem houses the largest collection of pre-Raphaelite paintings outside of the U.K.

Enchanting gardens surround a derelict mansion, all hidden in plain sight behind a stone wall.