OT: What was invented first, floors or stairs?

s0nk

One could think that they first invented the 2nd floor and then had to find a way to get up there.
However I tend to believe that it could have been the other way round, - that they first invented the stairs (or maybe discovered them, as stairs can be found naturally in nature). And when they had the stairs they got the idea to build another floor.
How do you guys think it happened?

easy29

Interesting thought. To continue this line of thought: How many floors did they build before they invented the elevator? Could it be that also the elevator was invented at a time when they only had a couple of floors? Was it the invention of the elevator that enabled them to start making 3rd, 4th floors and so on? But why would they invent an elevator if they only had a couple of floors?

futurevator

Stairs were invented first. They were invented as a way to move from one level of a building to another, and were essential for the construction of larger, multi-level structures. Floors were not invented until after stairs, as a way to provide a level surface for walking in those structures.