Unix was created in the 1960s at Bell Laboratories in New Jersey.
Mac OS X, which based on BSD which is from Berkley, CA 1977. 😈
Richard Stallman created a set of programs and libraries called GUN in 1983, but also created the idea of Free Software which later gave inspiration to Open Software via the GNU licence.
Linux, which is from a guy named Linux Torvalds in Finland 1991. 🐧
Both Android and iOS devices, like iPhones are based on these systems.