Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

An overlooked memorial honoring the local Washington residents who died in World War I.

A remarkable time capsule of American manufacturing deep in Maryland coal country.

An Industrial Revolution-era public work that purified water using nothing but sand.

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

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

Decades before the scandal, this staircase on the river was a literal "water gate."

The site of the climactic scene from the classic horror film is now a historic landmark.

This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

A 15th-century granary that played the role of futuristic slave quarters in the world of 'Star Wars.'

This Armenian monastery was carved out of cliffs and named after the spear used to stab Jesus.

Exact replica of the ancient monument, but much, much lighter.

The United States Capitol's former columns still stand.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.