Sahih al-Bukhari, Book 81, Hadith 142 (In-Book) ⓘ
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.
قَالَ أَبُو حَازِمٍ فَحَدَّثْتُ بِهِ النُّعْمَانَ بْنَ أَبِي عَيَّاشٍ، فَقَالَ حَدَّثَنِي أَبُو سَعِيدٍ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " إِنَّ فِي الْجَنَّةِ لَشَجَرَةً يَسِيرُ الرَّاكِبُ الْجَوَادَ الْمُضَمَّرَ السَّرِيعَ مِائَةَ عَامٍ، مَا يَقْطَعُهَا " .
also referenced under: Hadith 6553 (DarusSalam) & Volume 8, Book 76, Hadith 559 (USC-MSA)