How did Christopher Columbus play an important role in historical development?

He embodies the period of Iberian exploration. Right around the 1400s and 1500s, Spain and Portugal took the lead in naval exploration. Portugal got wrapped up in Africa, but Spain (Christopher Columbus was sent by King Ferdinand, as I'm sure you know) discovered America. If he hadn't discovered America, European diet would be drastically different (look up the term 'Columbian Exchange') and the influx of silver that helped to switch the balance of power from the East to the West (think the Ottoman Empire) wouldn't have happened. So in the end, Columbus ends up being a very stubborn Portuguese sailor sent by Spain to discover India, who ended up leading other conquistadors, privateers and explorers to completely change the agricultural, ecological and economic make up of the world.