Here is a clip of one of the all-time great sopranos, Joan Sutherland, performing the "Vissi d'arte" aria from the Act 2 of Puccini's opera "Tosca".
The tone and control she maintains when singing in the extreme high register, all while turning a beautiful phrase, is what all instrumentalists strive for. Truly incredible stuff.
And I love the subtlety of her vibrato. (At least subtle compared to a lot of other sopranos singing in that register!)