List vs tuples

[Mitja]

A neewbie's question here, probably discussed before:
what's the purpose of having both lists AND tuples?
At the first (and second and third, to be honest) glance lists are just
tuples with extended functionality, so why have tuples around?
I've been working with Python for a few months now but haven't yet come
across a problem that would really require tuples.

Thanks in advance,
Mitja