Camp Zhuravlev

Camp Zhuravlev is a high security Super prison in Siberia, Russia, and is considered to be the most secure super detainment facility in the entire world, with no known escapees so far.
Located in Zhuravlev Bay in Severnaya Zemlya, it is being operated by the Russian government and is one of its most tightly guarded secrets. As no press or visitors are allowed there, it is considered a black site by the international community, with rumours of severe human rights violations persistently surrounding the facility. Satelite pictures suggest that the camp is large enough to house hundreds of prisoners at minimum, though further underground facilities not visible on the pictures have been speculated about.