gold
Explanation:
Gold was numerous in the Americas:
The gold was ambitioned by European monarchs to be used as a international currency and mainly used to pay foreign debt as well as to finantiate war. Indeed the Cruzadas were funded by gold from the Americas.
Spain defeated the Incas, Aztecs and other civilizations and obtained acces to incredible amounts of gold.
Likewise Portugal became exploring the portions that correspond to Brazil. Sooner the British would sponsor piracy making loot from the Spanish vessels that came to the European continent.
The gold from the Americas amounted to Spain becoming the most powerful nation in economy and territory of the time.