Despite earlier naval expeditions undertaken for reasons of diplomacy or trade, it wasn't until the early 1400s that European maritime explorers established sea routes through most of the globe's inhabited regions, uniting a divided earth into a single system of navigation. From the early Portuguese and Spanish quests for gold and glory, to later scientific explorations of land and culture, this new understanding of the world's geography created global trade, built empires, defined taste and alliances of power, and began the journey toward the cultural, political, and economic globalization in which we live today.