The remains of this 2nd-century Roman temple are incorporated into a modern building.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

This small Roman arch was transformed into a dwelling by the founder of the Trinitarian Order.

A Nesting Doll of Churches.

A rather vulgar example of the transition from Latin to the Italian vernacular.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

Stone memorial that's said to predict the death of the pope and the site of the Cadaver Synod.

Museum dedicated to literary greats of the Romantic Period is also the home in which Keats met his untimely end.

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

A sculpture serving as an homage to Pope John Paul II.

Its interior is adorned with some of the best examples of early Christian mosaics.

Ancient ruins hidden underneath a modern luxury hotel.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

A monumental fountain in Rome features a large statue of Moses that has been criticized for centuries.

Architectural monsters are devouring this palace's every door and window.

This subterranean oyster house has been the pearl of Grand Central Station since 1913.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Rat sculptures try to infiltrate the Graybar Building in an architectural tribute to New York City's nautical history.

The park is home to the United States's only still-operating Dutch windmill.

Outside Hope College in Holland, Michigan, a marker honors a University without people from the fictional Kcymaerxthaereal times.

On the shores of Lake Kalamazoo, a plaque marks a fictional event where an island nation ran aground.

This is the last hand-cranked chain ferry of its kind in operation in the United States.

In this quiet park a rendition of a classic painting graces the outside of a charming restroom.

In an alley not far from where two great highways meet, byways of a very different sort are honored.