What refers to ultra-high-security prisons?

Ultra-high-security prisons, often referred to as "supermax" facilities, are designed to house the most dangerous and high-risk inmates, including those convicted of violent crimes and notorious offenders. These institutions feature strict security measures, such as solitary confinement, advanced surveillance systems, and limited inmate movement to prevent escapes and maintain order. The goal is to isolate these individuals from the general prison population to minimize threats and ensure safety. Examples include the ADX Florence in Colorado, which is known for housing some of the most infamous criminals in the U.S.