(132) باب التَّسْبِيحِ إِذَا هَبَطَ وَادِيًا
Narrated Jabir bin `Abdullah:
Whenever we went up a place we would say, "Allahu--Akbar (i.e. Allah is Greater)", and whenever we went down a place we would say, "Subhan Allah."
Reference: Sahih al-Bukhari 2993
In-book reference: Book 56, Hadith 202
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 52, Hadith 236