He got into hiking in his 20s, but it was trekking and scrambling in little know wilderness on four continents visited on his five-year-long H.M.S. Beagle voyage between 1831 and 1836 that cement him as one of the most worldly hikers in history.
“Mount Darwin” is the highest peak in Tierra del Fuego. On February 12, 1834, Captain FitzRoy named a mountain after him on his birthday. …
Darwin walked mainly to discover plants and animals unique to those regions.
I learned all this by reading his travelogue Voyage of the Beagle.
By the way, the famous phrase “survival of the fittest” comes from Herbert Spencer’s 1864 publication, “Principles of Biology.” The term is largely thought to have been coined by Darwin regarding his thoughts on evolution; however, this is a wrong assumption.