(CTV News) Archeologists confirmed a long-time suspicion of historians and say that famed Alcatraz prison was built over a Civil War-era military fortification.
Researchers found a series of buildings and tunnels under the prison yard of Alcatraz Federal Penitentiary, which once held Al Capone, SFGate reported Tuesday.
A study published last week in "Near Surface Geophysics" said archaeologists used ground-penetrating radar and terrestrial laser scans and historical maps and photographs. They found fully buried structures, ammunition magazines and tunnels.
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