Pilgrimmage (Hajj) 
Bukhari :: Book 2 :: Volume 26 :: Hadith 819
Narrated Ibn Abbas:
Staying at Al-Mahassab is not one of the ceremonies (of Hajj), but Al-Mahassab is a place where Allah's Apostle camped (during his Hajjat-ul-wida).
Pilgrimmage (Hajj)
Bukhari :: Book 2 :: Volume 26 :: Hadith 819
Narrated Ibn Abbas:
Staying at Al-Mahassab is not one of the ceremonies (of Hajj), but Al-Mahassab is a place where Allah's Apostle camped (during his Hajjat-ul-wida).