The player's towns serve many functions, but most importantly they allow recruitment of creatures to form armies. Towns also provide funds, new spells and a fortified location to make a last stand against an invading enemy hero. To build new structures within a town requires gold and usually one or more type of resource. Wood and ore are needed for most structures, but more expensive buildings also require rarer resources (mercury, crystal, gems or sulfur). All factions require a disproportionate quantity of just one of these special resources, making the acquisition of a corresponding mine essential to victory. This same resource is also needed when hiring the most powerful creatures available to that faction. Each faction also has a handful of unique structures available only to them.