A former waterfront market is now in the center of town due to some interesting Boston engineering.

This massive tea kettle was once a promotional stunt for the Oriental Teashop.

Ice cream stand, snack bar, and time capsule of milk conveyance.

The American Revolution was galvanized into serious action due to the tragic clash with British soldiers that occurred at this location.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

Famously misunderstood wonder of the ancient world

This narrow coastline trail through the dense Kauai wilderness is among the most beautiful and dangerous in the world.

This blowhole is supposedly caused by a trapped monster.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

When flour explodes, it's not a pretty sight.

The tomb was guarded by soldiers from both sides of the war, and some left their initials carved in the brick.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

The romance of early commercial flight still fills this Art Deco destination.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

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 little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

It was once the base for a series of domestic terror attacks.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

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

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.