Breathtaking and huge 430 year old maps of Italy.

One woman's Viking Castle on Lake Tahoe.

The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

The Empire Mine is "one of the oldest, largest, deepest, longest and richest gold mines in California."

This former boomtown "island" is now submerged below Folsom Lake.

Dentist's hated concrete colossi are now beloved icons of the community.

This 19th century hydroelectric powerhouse was the first of its kind.