It gets its unofficial name from a prisoner-constructed[2] sculpture depicting a black dolphin, which is set in front of the main entrance.

The prison houses approximately 700 of Russia's worst criminals, including child molesters, murderers, terrorists, cannibals, and serial killers.

For 90 minutes a day, they exercise in a large cage; during this time, cells are searched for contraband or illegal items.

Inmates are also under 24-hour surveillance and supervision; they are forced to stand and forbidden from resting or sitting on their bunks from the time they awake until bedtime (roughly 16 hours).

The prisoners are fed soup four times a day,[3][better source needed] and are only allowed books, newspapers, and a radio.