Srutakirti: Brahmacari: 'Srila Prabhupada, it says in one of the stories from the Krishna book that Krishna and Balarama jumped off a mountain 88 miles high. Where is this mountain located?'
Srila Prabhupada: "In the sky."
Reference:Srila Prabhupada Uvacha by Srtuakirti Dasa