We generally love to live by the rivers, at least on weekends, and banks are rife with such contraptions, specially splav type (i.e. raft). Just look closely at the banks of Sava near Belgrade on satellite view - there are hundreds of them, many converted into taverns, often being rather original designs and/or makeshift contraptions.
For the one on the picture, I didn't expect it to be so far upstream on Drina - Bajina Bašta (Baja's Garden :) is rather deep in the mountains, and the river should be rather fast there. I thought it's the other one, in Đerdap, which is a weird lake where Danube flows as a border river between Serbia and Romania.
