From Sahih Bukhari (Hadith 1535):
Narrated Musa bin `Uqba:Salim bin `Abdullah's father said, "The Prophet (ﷺ) said that while resting in the bottom of the valley at Muarras in Dhul-Hulaifa, he had been addressed in a dream: 'You are verily in a blessed valley.' " Salim made us to dismount from our camels at the place where `Abdullah used to dismount, aiming at the place where Allah's Messenger (ﷺ) had rested and it was below the Mosque situated in the middle of the valley in between them (the residence) and the road
Reference: Bukhari 1535