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

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

A monument marks the location of the first successful steamboat demonstration.

This advertisement for talcum powder was painted on the rock face and has since defied removal.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

Every drop of D.C. tap water flows through this old waterworks.

The span is crooked and made from two older recycled bridges.

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

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

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

One man's love of natural beauty led to the creation of this hidden granite monument.

At night, a grove of towering redwood trees growing through the pavement block out all light from the so-called “Dark Park” of Madrone Avenue.

Ride on a fully-restored Nike nuclear-tipped missile elevator from the Cold War.

Internationally-recognized arts center housed in a century-old former military barracks.

This lighthouse has been guiding shipping into the Golden Gate since before the American Civil War.

The grand, column-fronted, sculpture-adorned home of the ambitious digital library.

A living time capsule of the 1960s Richardson Bay water-front.

Discover for yourself what Herb Caen referred to as "the best kept secret in the Bay Area."

Astronomers plan to launch a space telescope into orbit, to find out what exactly stands in the way of an asteroid hitting Earth.

Concrete strongholds stand guard over the Golden Gate.

George Lucas donated this park to honor the birthplace of his two biggest movie franchises.

Centuries of biking history are nestled in the shadow of the birthplace of contemporary mountain biking.