Alcatraz is a small island in San Francisco Bay, 1.5 miles from San Francisco.
From Alcatraz, you can see the famous Golden Gate Bridge.
Alcatraz is also famous and is now a major tourist attraction.
Tourists can reach the island by boat from the city.
Alcatraz has often appeared in movies, including "Escape from Alcatraz" which was made in 1979.
One reason it’s famous is because it used to be a prison, a very special prison.
It was designed for prisoners who were causing trouble in other prisons, such as trying to escape.
It was a maximum security prison, so escape was almost impossible.
The waters around it are cold, and only very strong swimmers can swim from the island to San Francisco.
The first group of prisoners arrived in 1934.
There were 137 prisoners, including bank robbers and murderers.
They came by train from another prison in the state of Kansas.
During that trip there was heavy security.
The prisoners were under guard and handcuffed.
Nobody wanted them to escape.
