SAN FRANCISCO, Ca. – Rumors and myths of hidden military bases and underground bunkers are nothing new. Alcatraz speaks volumes to this! Earlier this year, Near Surface Geophysics released a report on the Civil War age military base revealed beneath the surface of the tour attraction/ ex-penitentiary.

PBS’ Nova and MentalFloss report that non-invasive techniques involving laser scans and radar systems were used to reveal that the intricate militant maze under the Alcatraz Penitentiary. Alcatraz, once thought to be among the most secure of prisons, housed infamous criminals and gang lords such as Al Capone.

However, the average citizen may not know that the United States’ history of utilizing this small island dates back to the Mid-19th Century. At that time, this barren island was transformed into a military base, but its usefulness as such was short lived due to military advancements and exponential growth in warfare taking place following the American Civil War. Not able to hold pace, military efforts on Alcatraz were terminated, and the external half of the base was built over with the Penitentiary that Alcatraz is known for in modern day society.