The oldest continuously operating fish market in the United States.

A celebrity from the late Cretaceous period.

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

Washington's iconic carousel has a nice piece of Civil Rights history.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

The most accurate timepiece in the world.

A small triangle of DC grass is the final resting place of one of Sonny and Cher's songs.

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.

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

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

Light bulbs, scrap wood, and tinfoil comprise this homemade throne of the gods.

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

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

Largest Roman Catholic church in North America.

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

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

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

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

Home to items never before seen by the public.

The United States Capitol's former columns still stand.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

A former major munitions plant that has been converted into a sprawling art space.

This grave marks the passing of a historic Jane Doe whose identity remains a mystery to this day.

Who needs fancy modern water slides when this giant North Carolina rock works just as well?