At one time, when digital computers have not existed yet or they lacked sufficient performance, the analog computers were widely used (even the ancient Antikythera mechanism and the slide rule can be considered as analog computing devices). The advent and rapid progress of digital computers made analog computers largely obsolete in 1950s and 1960s, though they remain in use in some specific applications, like the flight computer in aircraft, and for teaching control systems in universities. Nevertheless several amazing analog computers deserve our attention...

South Pointing Chariot Astrolabe
Sector Vladimir Lukianov (1936)
People say nothing is impossible, but I do nothing every day.
Winnie-the-Pooh