What if Columbus did find a route to India, and the only ones to find America were Vikings?
What if Sir Isaac Newton wasn't born?
What if the New Kids on the Block were never brought together? [The world wouldn't be here.]
What if the calculations from America and England on D-Day were correct, and they never landed in Normandy?
What if NINTENDO was NEVER CREATED?
What if the Titanic didn't sink?
What if the Roman Empire won all battles?
What if the Bermuda Triangle was really a mine field?
What if Francis Ferdinand was never assassinated, and WW1 never started?
What if plankton didn't exist? (Ouch.)