Minecraft wiki entry for Building_a_metropolis, associated text: One light source for a metropolis is lampposts. A lamppost can be built with a redstone lamp hooked up to an inverted daylight detector so that the lamp will turn on when it gets dark. You can also use a torch, as you can put them in houses. Another indoor lighting trick is to put the light source under carpets. The source of light will be hidden from sight, but the light will still shine through the carpets.