In Grepolis, you may build buildings in order to expand your polis or village. Every building has a different function, whether it would be to order the construction of other buildings, for the recruitment of units, for resources and others. Most buildings have requirements also, which must be built before the building may be built. All buildings are built through the Senat and each building gives you points.
There are also eight special buildings which give your village a unique bonus. You may only build one from each side, so plan on which special building you want to get.