Every one is unique in there own special way. you are the only one like you. Even if you have an identical twin. there are still many, many ways that the two of you are different, even if you can't...
Because no one else is exacly like you. You're you and no one can change who you are.
The 2nd, A unique
An unique, an university, an European, etc are desperately pedantic.
an unique is wrong.