As the name suggests, players are separated by the raging Amazon river in both team and free-for-all battles. In a team battle, all players in that team will be placed on one side of the river, while the other is placed across them. In a free-for-all, an equal amount of players are put on each side (so in an 8-man free-for-all, four players are put on both sides).
A trade route usually cuts through each side, with three trading post sites in them. In the original version, Tupi, Carib, Inca and Aztec tribes can be found, while in the Warchiefs expansion, the Aztecs are replaced by the Zapotec due to the Aztecs being a playable nation.
To invade players on the other side, the player will need to construct ships to ferry units over to the other side. The river contains large numbers of Bass and is subjected to heavy naval battles as teams send their navies to battle along the river and to ferry their armies into enemy territory. Team players are advised to construct Castles,Outposts, or War Huts along the shores to damage/sink enemy ships; in free-for-all battles, it is better to put them around the settlement due to the length of the river.
"The Amazon basin is drained by over a thousand tributaries that empty into the massive Amazon River, which in turn dumps millions of gallons of fresh water into the ocean per second. The Amazon River is over 6,000 miles long and more than 24 miles wide at its widest point. An astonishing variety of plants and animals live in the rain forest, including capybara, sloths, macawss and millions of insect species, all living in different strata of the forest, from the tops of the tall trees to the dirt and streams below, and everywhere in between.
The Spanish Conquistador Francisco de Orellana was the first European to successfully navigate the length of the Amazon River. Virtually all of his men died in the voyage; when he returned to Spain, Orellana told of attacks on his men by a group of fierce warrior women. In reality, the attackers were probably long-haired men. He likened his assailants to the Amazon women of Greek mythology and the name stuck."