Automated Teller Machines, either at a bank or at some other place. These commonly feature a CPU based off of either MIPS or x86, and have an operating system that's either Windows or Unix based. In the past, it appears that almost all ATMs ran off of Windows variants, such as Windows 2000, Windows XP, or Windows 7. Nowadays, however, the dominance of Windows continues, but with a small input from Unix-based ATMs.

Little is said about this, but it runs Windows 2000. Some good general info in the thread.

https://www.reddit.com/r/hacking/comments/b30psu/shut_up_and_takey_money_atm_in_argentina/