The world of Bronze Age is divided into many different regions, each of which has a dominant biome. This biome controls the plants, animals, and resources available in the region, as well as the terrain.
Forests are densely packed with trees, interspersed with winding paths of grass. They are excellent sources of Logs, but any substantial construction will require a lot of time spent clearing land.
An awkward combination of shallow water, dense trees, and fertile soil; the Swamp is both a unique challenge to city builders and an interesting tactical situation for warlords.
Savannah can be identified as large empty plains of barren grass. They are relatively poor in resources, with only occasional clumps of trees. Wild pigs can be found here, however.
Deserts are featureless plains of sand, with no resources or animals whatsoever.
Grasslands are mostly empty plains of grass, interspersed with clumps of trees and wild pigs. Fertile soil can be found along the banks of rivers.
Oceans are impassible as of 2.0, and don't have any resources.
Mountains are large areas of rock, any sort of construction will require considerable work clearing the ground, but mountains also contain a wealth of resources in the form of Limestone and Copper Ore.
Highlands have a mix of rock outcroppings and trees, with the occasional wild pig. Small Limestone and Copper Ore deposits can be found here, and are much more accessible than mountains due to the flatter terrain.