Sahih Bukhari
Prophetic Commentary on the Quran (Tafseer of the Prophet (PBUH))
Volume: 006 / Book Number: 060 / Hadith Number: 387
During the lifetime of Allah's Apostle the moon was split into two parts; one part remained over the mountain, and the other part went beyond the mountain. On that, Allah's Apostle said, "Witness this miracle."