A one-of-a-kind sundial at the Very Large Array honors a radio astronomy pioneer, incorporating the original piers from his breakthrough radio telescope.

This opulent Pueblo Deco movie palace melds Art Deco and Native American motifs.

Thousands of pieces of art have been carved into the rock at the site of an ancient volcanic eruption.

This museum started as a collection of Manhattan Projects and continues to add exhibits as they are declassified.

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

A preserve with 75,000 ancient drawings remains the realm of public – not just scientific – exploration.

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

These Pre-Columbian petroglyphs contain representations of birds, deer, hunters, and even some early Native flute players.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

This dig site outside D.C. is known for its exceptionally high density of baby dinosaur fossils and dinosaur eggs.

A relic of FDR's brief foray into utopian urban planning.

The development and impact of electronic media showcased in a picturesque farmhouse in Maryland.

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

A historic Maryland home that once belonged to a man who has been called "the most insignificant" U.S. Supreme Court justice.

Visitors to this library are in for a real-world education in modernist architecture.

The only Leonardo Da Vinci painting in the Western Hemisphere.

The National Park Service’s best-kept secret with views that rival any in D.C.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

Art deco landmark on the outskirts of Washington, D.C.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

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 "lovely red Vega" of the legendary record-settling pilot.