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.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

A celebrity from the late Cretaceous period.

A computer bug so primitive it was an actual insect.

An obscure public service from the U.S. government that redeems burnt, moldy, and soiled old greenbacks.

The oldest continuously operating fish market in the United States.

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

The most decorated dog of World War I is preserved in the Smithsonian.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

The walls of the iconic dome are hollow and have a secret stairway.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

A wondrous old library overlooking the nation's capital.

A historic neighborhood church is reborn as a psychedelic arts collective.

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

Home to items never before seen by the public.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

A shining sculpture made of 3,115 lights, the number of visible stars in the Northern Hemisphere.

Mysterious 500-year-old tapestries depict a unicorn hunt.

The highest point in Maine is a grand gift to the state citizens that also happens to be one end of the Appalachian Trail.

True to its name, this bouncy walkway may be the world’s smallest suspension bridge.

The oldest still-operating tavern in the United States was once owned by a pirate.

A railroad magnate's replica village has become home to a genetic seed bank for rare breeds of livestock.

Get a close look at the gigantic remains of long-extinct mammoths.

A "time traveler's" vision of human history stretches throughout Mexico City's Copilco metro station.