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

Thanks to an acoustic anomaly, this unassuming stone bench has heard one hundred years of secrets.

This museum tucked below a charming cafe gives a brief snapshot of photographic history.

St. Francesca Romana, patron saint of drivers, resides in the church she founded.

A Nesting Doll of Churches.

A new sculpture calls attention to climate change in the centuries-old city it threatens.

The yawning maw of this pagan visage is said to bite off the hands of liars.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

Follow the original medieval paths that wind through this intriguing section of the city.

The sculptor was instructed to add “stallion attributes” to the general's bronze mare.

This ratty natural history collection is a charming relic among a city rushing into modernity.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

The "lovely red Vega" of the legendary record-settling pilot.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

The grand marble structure next to the White House is Andrew Carnegie's temple to Pan-American diplomacy.

Look closely and you’ll notice that the color changes a third of the way up the tower.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

Home to items never before seen by the public.

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.