how did fountains work in older times

i recently watch Mughal-e-Azam, superhit Boolywood Blockbuster. It shows fountains running all over the palace of Akbar (around 400 years before from now). There are evidences supporting existence of fountains in ancient times.

My question is that how did the fountains work in those times? If we notice fountains today, they are driven by electricity. but there was no such thing in ancient times which could support fountains. so how did they work?? I can't think of a possible answer. Do you have an explanation for that!!!