Jan Koum
(Ukrainian Soviet Union→ US)
He started off as a cleaner in a grocery store, but a little something called Whatsapp changed all of that. Koum is the revolutionary app’s co-founder and CEO. Facebook Inc. acquired Whatsapp in 2014 for $19 billion, making Koum a very, very successful man.
Fun fact: Before founding Whatsapp with Brian Acton, the two worked at Yahoo. They then quit and travelled around South America together, apparently playing lots of ultimate frisbee.