Translation:I am standing beside the wide river, at the famous clock.
Yes, that should be accepted. (I'm pretty sure I've entered that myself, and reported it.)
just to be clear -nel means by, at, near it and mellett is literally next to it (to the side of it)?
Exactly. But watch out, -nál/-nél doesnt literally mean near to something, it just refers to it. "By" and "at" already carry the meaning of near. (by the window - ablaknál, at the table - asztalnál, at my friend('s place) - a barátomnál) (The literal translation of "near to something" or "close to something" is "közel valamihez".) Because if you agreed with your friend to meet at 8 pm at the XY grocery store for example and he calls you at 7:55 asking you where you are, if you say you are at the store (a boltnál) that means you are already there but if you are near to the store (közel a bolthoz), you haven't arrived yet.
What is the difference between "by the wide river at the famous clock" and"at the famous clock by the wide river" it is rather frustrating...