Untill recently, (the last 6,000 years) humans have been mostly normadic, moving around as need be. Most of the human-built structures were simple huts or tents, which did not take long to build.
The exact time is not known, but around 10,000 years ago, humans figures out that it is much more efficent to farm rather than gather. Whan humans started farming, our structures changed, too. They became much stronger (before, they wouldn't have to last very long) and stable. They also offered a stable living place, protection from the rigors of life. it would still take a long time for them to develop into the structures we know today.
Types of buildings in prehistoric times:
1. Hut: a small, easily built structure designed to provide basic protection.
2. Tent: a simple portable structure genrally made out of skins.
3. Mud-brick building: Probably the most complex of the three, a simple building made out of dried mud. This may or may not be supported by timber.