Its diverse collection of computers and technology spans the ages.

A swimming hole in the historic industrial quarry that supplied the marble for the Baltimore Washington Monument.

An intricately designed junk art house with four extravagant junk art cars hidden in the suburbs.

A relic of FDR's brief foray into utopian urban planning.

Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

The Corinthian columns that towered over Abraham Lincoln’s inauguration stand proud.

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

Once part of a dam servicing an early 19th century grist mill, the tucked-way falls are a tricky-to-find urban oasis.

A winding district gerrymandered into the shape of a mantis.

An echo chamber with a waterfall wrapped around its base at the Embassy of Canada in Washington, D.C.

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

Politicians, bureaucrats, and military officers gathered in this field near the Capitol to settle their disputes with blood.

A historic cemetery with unique artwork, a Civil War fort, and also happens to be the site of the Battle of Bladensburg.

In October 1856, Harriet Tubman escaped arrest at this site while attempting to reunite an enslaved woman named Tilly with her fiancé.

In Stone Town, Zanzibar, the city’s culture and history is told through its doors.

This library is designed to commemorate the work of the Human Genome Project.

I-95's Tijuana-style celebration of kitsch at the Carolina border.

This shifting North Carolina sand dune is an odd little desert surrounded by oceanic forest life.

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

Rumor has it the hot dog stand was targeted by two Russian nuclear missiles.

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

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

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

These unusual rooms on wheels are holdovers from the 1960s.