A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

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

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

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

Home to items never before seen by the public.

They sort through millions of dollars worth of diplomatic gifts on behalf of the government.

The grand marble structure next to the White House is Andrew Carnegie's temple to Pan-American diplomacy.

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

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

This mysterious underground cave in Shropshire dates back to the 18th or 19th century.

The painted and decorated towers of this Hindu shrine were once the tallest structures in one of the oldest cities in India.

This dramatic landscape hidden on the Isle of Skye looks as though you've stepped into the magical realm.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

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

This grand gothic brewery has been pumping out suds for over a hundred years.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

Daily lunch spot for many of Washington, D.C.'s cab drivers.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

One woman’s obsession gave birth to this lovely oddity at the Boston Public Library.

Dioramas and animatronics lead you through the story of Bhagavad-gita, the Indian literary classic.

A wonderfully strange collection of 500+ stuffed frogs doing people things.

32,000 tiny soldiers are posed in 23 historical settings.