Volume 8 · Book 76 · Hadith 559e
Narrated Abu Sa'id: The Prophet said: There is a tree in Paradise (so huge) that a fast (or a trained) rider may travel: for one hundred years without being able to cross it.
— Sahih Bukhari, Volume 8, Book 76: To make the Heart Tender (Ar-Riqaq), Hadith #559e