Will WW3 happen?

[Redalgo]

It already happened.  Ever heard of the Cold War?

Yeah, this is basically what I was going to post here. There were stand-offs on most continents, proxy wars fought in many countries, governments toppled, shifting networks of allies / satellites established, and so on. Fear of nuclear warfare simply forced a new style of global conflict that was less direct than what was experienced during the first two world wars.