Nobody knows when the first person began to chew gobs of sap from trees, but it was probably before they were really even people. Certainly somebody was chewing gobs of tree sap as early as 3000 BC in Finland. People also chewed gum in ancient Greece, early North America, and pretty much everywhere else in the world.
But the best gum was the gum of the Manilkara tree or the sapodilla tree – chicle to Aztec or Maya people – and those trees only grew in Central America. These trees are closely related to rubber trees, which also grow in Central America. You get the gum the same way you get rubber: you make small cuts in the bark of the tree, and the sap oozes out through the cuts. Then you boil it like maple syrup until it is the right thickness.