Here's a suggestion, but if anyone else asks you for something, do theirs first. And if you don't like this one, you don't have to do it. You've already been very generous to me.
A crystal temple rising out of the water in a lake. The temple is dedicated to a goddess of water and sky, and so the temple walls reflect both. It's got 6 tall bell towers, each with several bells at different levels. There is one door into the temple, but no causeway to get to it, since they really don't want visitors.