Scientist Pete Kelsey and his team have 3D-mapped the entire island of Alcatraz, discovering Civil War secrets, prisoner escape routes – and looking at ways to preserve the island for the future.

This is because Alcatraz is rich with history ... it was a military prison that housed prisoners from the Spanish-American War and Civil War, as well as the site of the West Coast's first ...

The federal government built the Pacific Coast’s first lighthouse on Alcatraz in 1854, and the Army constructed a fort there, where it imprisoned Confederate soldiers during the Civil War.