In order to get an oral examination done I've read stuff about

• Roenten tubes: Operating voltages: lets say 15 to 80 kV (yes, k is for kilo and that means: *1000)
• CT Scanners: Operating voltages 60 to 120 kV
• MegaVolt CT Cancer therapy device: Operating voltages up to 6 MV (= 6000 kV)

Tried to start my car without success: Operating voltage of the battery in my car: 0 V

(Yeah, I know, that's probably not correct, though it's a nice story.)