A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

Herbert Hoover's "Brown House" rural presidential retreat was a PR disaster amid the start of the Great Depression.

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

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

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

Every autumn, this grove of living fossils erupts in a blaze of brilliant golden-yellow leaves and stinky fruit.

The eccentric mansion of one the most popular horror authors of modern times.

These buildings are a poignant reminder of the thousands of horses and mules who passed through this area of the Shenandoah Valley on their way to war.

This sprawling farm was once a Cold War-era hideaway for the nation's top diplomats.

An almost life-sized elephant named Ms. Ellie greets visitors at this jumbo-themed museum.

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

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

Time travel with sweets across history at this research-based candy store.

Little has changed in the way that this mill operates since the 18th-century.

Built by the patriotic residents of Boonsboro in a single day.

An eponymous directional signpost erected by the first president of the United States.

Outsider art meets paleontology at this roadside reptile repository.

The Grand Ole Opry's big voice came from a small home in rural Virginia where she was eventually buried.

A giant time capsule not scheduled to be cored until 2040.

A natural spring situated on the grounds of the Hawthorne estate.

Extraordinary objects lurk in this quintessential regional museum.

Berkeley Hot Springs presents to you "the only outdoor monument to presidential bathing."