What made columbus find a different route to the indies?

Because it was a must if the Europeans wanted to keep trading with the East (mostly spice markets) since the Turkish had occupied all the land routes to the East. The caravans were nor safe any more (and they had not been safe before either), so some adventurous sailors decided to find new routes , that is new ways to reach the Indies. The pioneers were the Portuguese who made the fastest and the best ships (the caravels) and founded the first school of navigation (new maps, rudder, used compass, etc).