A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

Exact replica of the ancient monument, but much, much lighter.

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

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

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

A former Confederate hospital serves as a remembrance of wounded and dead soldiers.

Within this lovely Richmond cemetery lie the remains of famous Virginians and some of Edgar Allan Poe's most beloved family and friends.

Inspired by a foil-wrapped potato, (seriously) the Markel Building has been deemed one of the 10 ugliest buildings in the world.

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

This historic mansion was built as a symbol of love between a husband and wife.

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

The ruins of this Thomas-Jefferson-designed mansion have been left to crumble since the Christmas Day they burnt down.

This 29-ton granite ball spins around at the slightest touch thanks to a scientific phenomenon.

The final resting place of two (or three) presidents, one vampire, and 18,000 Confederate soldiers.

An artist's cute bronze subway sculptures belie his violent artistic past.

A notorious punk house turned co-op.