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

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

This scalding hot river was thought to be a myth until one geoscientist made it his quest to study the mystical waters.

This folk art wall claims to be the world's one and only memorial to the bygone age of hippies.

These massive concrete balls were used to mine gold in Virginia.

A shrine on the shores of the Tigris.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.