The Minish Cap
Veil Springs is a location in The Minish Cap at the tip of Veil Falls. Here, Link can find an updraft that leads to the Cloud Tops.
Biggoron can be found here after Link fuses Kinstones with a Goron in the Goron Cave. If Link gives Biggoron his shield, Biggoron will chew on it and spit out the Mirror Shield, which Link can claim.