Narrated Anas:
The people of Mecca asked the Prophet (ﷺ) to show them a sign (miracle). So he showed them (the miracle) of the cleaving of the moon. (DE)
USC-MSA web (English) reference: Vol. 6, Book 60, Hadith 390 (DE)
Arabic reference (DE): Book 65, Hadith 4867 (DE)