At 207 feet, one of the world's longest continuous escalators.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

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

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

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

Home to items never before seen by the public.

The only National Monument ever to go missing for nearly 50 years then resurface in a dump.

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

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

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

A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

A hidden passageway now marks the site of an assassination attempt on Ronald Reagan that some say broke a 140-year-old curse.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

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

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

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.

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

The castle that provided the setting for much of 'Monty Python and the Holy Grail' is now a pilgrimage site for fans.

Cascading waterfalls mark the gateway to the ancient burial place of Clan Macnab.

One of Scotland's earliest hydroelectric power stations.

This Neolithic stone circle is the most complete of its kind in Scotland.

A rare example of traditional ‘common’ Highlands housing from the 18th century, with minimal changes and a potential murder scene

An exceptional engineering feat that facilitates the migration of salmon upstream during their breeding season.

Old-fashioned knowledge and modern engineering create the world's only rotating boatlift.