There are two "layers" to the world map: the aboveground and the underground. There are typically subterranean gateways that lead to and from the underground. Maps are filled with a huge variety of buildings, treasures, monsters, mines and so forth that reward extensive exploration. At the very least, a player must locate mines and flag them (whereupon they provide constant resources), since these resources are required to develop towns. The player must also develop their heroes' skills, both by battling creatures (and enemy heroes) and by acquiring artifacts or visiting special locations. Heroes are given a choice of skills to upgrade upon leveling up, as well as becoming better at combat or using magic. The skills must be chosen carefully, since they are permanent and only a limited number of skills can be learned.