The highest bridge in America was built for an almost unnervingly small amount of money.

This Colorado hiking trail provides a small gold mine of abandoned gold mines.

Small teepee-like houses built for TB patients have become sheds, studios, and bus stops around Colorado Springs.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

The elevator that makes it possible to fly American flags in bulk over the U.S. Capitol

The king of U.S. high points towers over every other peak on the continent.

One of two side-by-side totem pole parks dedicated to educating visitors on Tlingit history and culture.

The first Russian Orthodox church in North America and an Alaskan landmark.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

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

Mortarless walls that stretch for miles are a lovely solution for creating grazing land in the harsh terrain of the Aran Islands.

A computer bug so primitive it was an actual insect.

South Carolina's last remaining slavery auction house is now a museum devoted to its own tragic history.

Dr Barnes' $25 billion private collection of art and arboretum.

The first American department store, and home to the largest operating musical instrument in the world.

This little-known collection holds everything from "Dracula" notes, to the manuscript of "Ulysses," to the forged works of Shakespeare.

Behemoth, cannon-like telescope operated by generations of Irish earls.

An Iron Age fort on the edge of a seaside cliff offers a glimpse into an ancient, mystical world.

While only two of the ancient buildings at this site are actually churches this was one of the earliest Irish pilgrimage sites ever.

The somber sculptures commemorating Irish Famine on the river Liffey in Dublin.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

This legendary city has been a tourist attraction for centuries.