  We use the recently established existence and regularity of area and energy
minimizing discs in metric spaces to obtain canonical parametrizations of
metric surfaces. Our approach yields a new and conceptually simple proof of a
well-known theorem of Bonk and Kleiner on the existence of quasisymmetric
parametrizations of linearly locally connected, Ahlfors $2$-regular metric
$2$-spheres. Generalizations and applications to the geometry of such surfaces
are described.
