This small museum gives visitors a chance to soak up the history of the "sponge capital of the world."

The sign that drew attention to a young boy's cucumber stand is now the name of his fruit superstore.

In memory of the 110 victims of ValuJet Flight 592 that crashed in the Everglades.

This splendid Versailles-inspired mansion has the largest French-style formal gardens in North America.

Although built to generate electricity for Marylanders, this dam has become an all-you-can-eat buffet for American bald eagles.

An astounding collection of medical specimens, including bits of President Lincoln.

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

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

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

Shoreline strewn with the remains of ghostly fallen trees.

A surreal landscape where fanged rocks rise from the ground and the ocean feels like a great mystery.

One of the few working locomotive roundhouses in the United States.

Thomas Jefferson's estate is home to hundreds of varieties of historic fruits and vegetables.

The story behind the mysterious symbol painted in front of the historic university's famous Rotunda.

There's an old indoor swimming pool hidden directly underneath the White House Press Briefing Room.

At 207 feet, one of the world's longest continuous escalators.

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

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

An original apothecary from 1792.

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

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

A lawn full of retired spacecraft on display at one of NASA's first research labs.

A priceless collection of the Nation's cryptologic history.

This English-inspired Maryland garden is home to acres of opulent plant life including bushes shaped into an entire fox hunt.