Will my atomic clock work in Europe?

Your atomic clock or wristwatch will certainly work if you're traveling to Europe or elsewhere in the world – it just won't automatically reset each day by radio signal from the U.S. atomic clock!
The radio signal from Fort Collins, Colorado using the WWVB transmitter has a limited range. Central Europe uses a German DCF signal transmitter and Britain, Ireland and Portugal use the British MSF time signal transmitter.
Your timepiece will work manually when you're away from the country and will update once you're back in range of the U.S. radio signal.