Abu Sa'id Al-Khudri (May Allah be pleased with him) said:
The Prophet ﷺ said, "There is a tree in Jannah that is so huge that if a rider of a swift horse has to cover its distance from one end to another in one hundred years, he will not be able to do so."

Another narration from Abu Hurairah (May Allah be pleased with him) is: The Messenger of Allah ﷺ said, "A rider will not be able to cross its (the tree's) shade even after travelling for one hundred years."

[Al-Bukhari and Muslim].

وعن أبي سعيد الخدري رضي الله عنه عن النبي ﷺ قال: "إن في الجنة لشجرة يسير الراكب الجواد المضمر السريع مائة سنة ما يقطعها " ((متفق عليه)). وروياه في "الصحيحين" أيضاً من رواية أبي هريرة رضي الله عنه قال: "يسير الراكب في سورة في ظلها سنة ما يقطعها".