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

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

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

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

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

Take an otherworldly journey in a school dedicated to out-of-body experiences.

The world's largest fully steerable radio telescope.

America's post-nuclear-attack chambers of Congress.

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

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

A psychological self-portrait in the form of a giant, segmented head.

Rural churches in the middle of nowhere with religious frescoes by famous artist.

The antique barns in Cameron are not painted with your grandfather's Mail Pouch Tobacco murals.

A historic covered bridge, only one of two remaining in North Carolina.

A 120-year-old legend concerning an empty circular patch in the North Carolina woods.

Jule Körner's house full of bizarre architectural details.

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

Taxidermy, Cigar Store Indians, A Model of a New York Tenement and Delicious Draft Root Beer.

The world's largest set of the ten commandments lay nestled in the heart of the Great Smoky Mountains.

Pink, packed sanctuary and home of the world's fullest-time Elvis fanatic.

Home to drunken tower-climbing goats... seriously.

Walk the whole Mississippi River!

An oversized metal construction of Billy Tripp's moods going through life.

Enormous lake at the bottom of a unique cave system.