- "Koshmar is not a hotel for petty criminals. If your friends are there, they must be insane, ruthless animals."
- —Yuri to Rip Hunter, Sara Lance and Leonard Snart[src]
Koshmar (Russian: Кошмар, lit. as Nightmare), also known as Nightmare Gulag, is a prison located in Moscow. According to Anatoly Knyazev, it is the worst prison in Russia. Anatoly, with his sarcasm stated the psychopaths and killers in the prison were only the guards and escape is nearly impossible.
Koshmar was built in the 18th century as the fifty-fourth labour camp.
In 1986, Vandal Savage used the gulag as a central location for his Soviet Firestorm operations. He had Martin Stein bribed, attempting to get him to finish the correct scientific formula, while having Ray Palmer and Mick Rory imprisoned and beaten to get Stein to cooperate. Despite Soviet Firestorm eventually being created, they were eventually all broken out by the rest of their team. They were able to unlink Stein and Valentina Vostok, causing the latter to become nuclearly unstable and explode.
In 2013, Lyla Michaels found Floyd Lawton in Koshmar. She attempted to break in and get him out, but was unable to leave. Due to this, John Diggle infiltrated the gulag with the help of Anatoly Knyazev. He was able to eventually find Lyla and escape, but they were hit with heavy fire, which they eventually broke through with Deadshot's help.
- Boris (deceased)
- John Diggle (escaped)
- Floyd Lawton (escaped; deceased)
- Lyla Michaels (escaped)
- Ray Palmer (escaped)
- Mick Rory (escaped)
- Martin Stein (escaped; deceased)