Among the established Sunnahs of the Prophet
is saying "Allahu Akbar" (magnifying Allah) when ascending and saying "Subhan Allah" (glorifying Allah) when descending.
Jabir (may Allah be pleased with him) reported:
"Whenever we went uphill, we would say 'Allahu Akbar,'
and whenever we went downhill, we would say 'Subhan Allah.'"
Thus, one magnifies Allah when ascending elevated places,
and glorifies Him when descending or going down a sloping path.