Atlantic World, of course, spiked post-1492: after the earliest European voyages to the New World and continuing encounters on the African coast, a Euro-centric division of the Atlantic was proclaimed between the Spanish Empire and the Portuguese Empire by the Treaty of Tordesillas in 1494. The West Coast and Central Africa, which are distinct from one another and each made up of many competing polities, played core roles in shaping the Atlantic World and as major sources for slave labor. An elaborate network of economic, geopolitical and cultural exchange took shape—an "Atlantic World" comparable to the "Mediterranean World". It linked the nations and peoples that inhabited the Atlantic litoral of North and South America, the Caribbean, Africa and Europe. The main empires that built the Atlantic World were the British, French, Spanish , Portuguese and Dutch; entrepreneurs from the United States played a role as well after 1789. Other countries, such as Sweden and Denmark, were active on a smaller scale. Historical usage American historian Bernard Bailyn traces the concept of the Atlantic World to an editorial published by journalist Walter Lippmann in 1917. The alliance of the United States and Great Britain in World War II, and the subsequent creation of NATO, heightened historians' interest in the history of interaction between societies on both sides of the Atlantic Ocean. Other scholars emphasize its intellectual origins in the more systematic and less political approach of the French Annales school, especially the influential work by Fernand Braudel on the Mediterranean World (trans. 2 vols, 1973). In American and British universities, Atlantic World history is supplementing (and possibly supplanting) the study of specific European colonial societies in the Americas, e.g. British North America or Spanish America. Some historians have criticized the North Atlantic emphasis as downplaying the importance of African history and the transatlantic slave trade on Brazilian and Caribbean history. Atlantic World history differs from traditional approaches to the history of European colonization in its emphasis on inter-regional and international comparisons and its attention to events and trends that transcended national borders. Atlantic World history emphasizes how the colonization of the Americas reshaped Africa and Europe, provided a foundation for later globalization, and insists that our understanding of the past benefits from looking beyond the nation state as our primary (or sole) category of analysis. Aspects Environment The beginning of extensive contact between Europe, Africa, and the Americas had sweeping implications