There are numerous buildings and structures on Alcatraz that are crumbling or no longer open to the public. I found these ruins very interesting and fun to photograph. Before the tour, I had no idea that prison guards and their families actually used to live on the island. The crumbled remains of their homes are nothing more than rock piles now. The island also had a bowling alley and small market for the families' use.
Another aspect of Alcatraz that I didn't learn about until our visit was that American Indians occupied the island in 1969 in protest of treatment of Indian tribes by the US Government. (The island had closed as a prison in 1963.) The group wanted to re-develop the island for use as a cultural center and education center, among other things. While this never happened, the occupation did result in President Nixon repealing legislation that had denied federal recognition of Indian tribes. Traces of the nearly-two year occupation are still seen on the island through graffiti. Look for the word "Free" on the American Eagle crest. "Indians" is on the water tower, but the rust makes it tough to see.
I can't imagine ever being in jail-- let alone in jail on an island. Alcatraz also had a seriously scary section of solitary confinement: "The Hole." The Hole was punishment for those who needed more isolation than basic solitary confinement. When the doors in The Hole were closed, the cells were completely dark. Yikes. The Hole is the final photo and a typical jail cell set-up is the first.