14 DAY TRIAL // A secret network of tunnels has been discovered recently beneath the infamous Alcatraz federal prison, bringing the facility situated on the San Francisco island into the spotlight once more.
The Alcatraz Federal Penitentiary was America's strongest and most notorious prison and was in use from 1934 to 1963. It was believed to be inescapable due to its location in the cold waters and strong currents of San Francisco Bay. Famous convicts like George “Machine Gun” Kelly, Mickey Cohen and Al Capone spent time locked up in Alcatraz prison's cells.
The penitentiary was shut down in 1963 due to concerns that rough weather might be affecting the integrity of the building. Nowadays, the jail is a tourist attraction, with more than a million visitors each year.
Using ground-penetrating radar technology, Texas A&M University researchers uncovered a very surprising piece of history lying underneath the former prison's walls, Yahoo News informs.
“The cart has a transmitter and a receiver — it sends an electromagnetic wave into the ground that then reflects off all the different structures underneath. Much like medical imaging would make a scan of the body, we are making a scan of the ground under the rec yard,” said Professor Mark Everett about the technology they used.
They discovered a labyrinth of tunnels dating back to the 19th century and an old keep that was thought to have been destroyed many years ago.
The tunnels were hidden underneath the prison's rec yard, the place where the inmates used to spend a single hour a week away from the confines of their cells.
The radar analysis conducted by the researchers revealed old fortifications dating back to long before the main building of the prison was constructed in 1915. They say the tunnel system is nearly 150 years old, so it dates back to the time when the island was used as a military fort.
When the American Civil War started, Alcatraz Island was transformed into a military base, complete with barracks and gun batteries. The researchers also found magazine buildings where ammunition was stored, as well as several other structures.
It seems that the hidden fortress was known to some historians, but the majority believed it had been destroyed many years ago when the massive federal prison was built.
For the moment, the buried discovery remains inaccessible, but archaeologists plan to start excavating the secret Alcatraz tunnels, although experts hope to learn more about the fortress without excessively disrupting the site.
They are also investigating the potential purpose of the network of tunnels, but they believe it can be related to the California gold rush of the mid-1800s.
“But what we don't really know is what exactly became of the fortifications, what state they are in and what is left of the cultural resources. And although it is not always desirable to excavate, with geophysics we can help people to know what is below the surface without actually disrupting it,” Professor Everett stated.