| Prerequisite advances:|
| Masonry (Civ1)|
Palace, City Walls, Great Wall, Pyramids
| Needed for further advances:|
Construction, Feudalism, Mathematics
The aggregation of people into the first cities required permanent buildings. To fill the need for these structures, some of the new city dwellers became expert in the techniques of Masonry. This technology utilized rocks and mud bricks, cementing these materials into buildings and walls. With experience, their buildings grew larger and more elaborate, walls became more imposing, and the work became more permanent and pleasing to the eye. Years of experience led to more sophisticated techniques of Construction.