Town Centers build Villagers. Town Centers also alow you to adance in ages. The ages are Stone, Tool, Bronze, and Iron. To advance in to the Tool it costs 500 Food. To advance into the Bronze it costs 800 Food. To advace into the Iron it costs 1000 food and 800 Gold. You always start in the Stone unless you play Nomad and then if you build your Town Center you are automatically in the Stone.