"Black Sites" and Secret Prisons

I had something about black box or black something come to mind and then found a description of a secret prison also named "black site".

These are locations or situations where a prisoner is held against their will and the UN or other bodies which have a right to inspection are not notified.

A "black project" is defined as the following:

In the United States and United Kingdom, a black project is a classified military/defense project, unacknowledged publicly by the government, military personnel, and defense contractors. Familiar examples of U.S. military aircraft developed as black projects are the F-117 Nighthawk stealth fighter and B-2 Spirit stealth bomber, which were highly classified and denied to exist until ready to be announced to the public.