Since the construction of Alcatraz finish, there have been 14 attempts that consisted of 36 inmates in total that tried to escape. This is what happened to them all:
2 drowned
5 weren't found (presumed they drowned)
6 were shot and killed
23 were captured
There was two people that escaped and never found. 3 people escaped and they were found. 56 years later and they have been never found. It's unknown if they were still alive or not.
In the 1850s, the US built an army fortress to protect the city of San Francisco but it was actually not used and needed, so, they brought it down and built a prison with the prisoners building it. It opened in 1934.
