Some friends of mine and I did a visit to Alcatraz last summer. We were on the evening tour so they opened the hospital wing. After the tour and exploring the hospital, there was a park ranger (they dress like guards) sitting on the bench. Her shift was up but the next boat was an hour and a half out.
Naturally I asked if she had any haunting stories....
She said, "Well, my script says no. But I have some free time so if your quiet about it, I will take you and your friends on another tour that is not part of this one exactly because the area is closed off to the public."
She took us up on the watch floor that looks down at every cell. No armed guards on the cell block. It was too dangerous. We then climbed up a super sketch stairwell to the Chappell. Nothing too exciting. But then she took us to the underground cells. Yup they have an underground. This is where they kept established Native American families living on the island when first establishing the prison. So many of them died that they have a little grave yard in the the center. Its a dirt floor.
The cells were covered in led paint. That's why it's not public. We got some really cool stories and history of the families. She then had us go into the cells to see the names and dates etched in the walls. While we were exploring, she turned off the lights and closed the main door.
Nothing crazy happened but man was that spooky.