Answer:
What can be seen but never found that only hides in the unwound?
Name for zenith
I am a box that holds keys without locks, yet they can unlock your soul.
In Paris but not in France, the thinnest of its siblings.
Two in a whole and four in a pair. And six in a trio you see. And eight's a quartet but what you must get. Is the name that fits just one of me?
I am your mother's brother's only brother in law. Who am I?