Why do we believe that Stone Age and Bronze Age peoples were building, what must have been quite labor intensive, stilted houses out onto bodies of water?

by Deadpan9

examples: https://en.wikipedia.org/wiki/Lake_Ohrid#/media/File:Museum_on_Water,_Ohrid.JPG

https://en.wikipedia.org/wiki/Pfahlbaumuseum_Unteruhldingen

http://www.cam.ac.uk/research/news/bronze-age-stilt-houses-unearthed-in-east-anglian-fens

GreensburgZombie

I'm sorry - what's the question? How they were built, or were they built by a later culture?