Two marabou storks came wheeling overhead, wings like black sails; my eyes followed them until they became dots in the landscape. Mankind began here. That’s the theory. Among the cactus-studded plains and steaming lakes of Kenya’s Great Rift Valley, it’s said that our forebears first graduated from four legs to two. Hominid skeletons have been found here dating back some six million years, which is a stirring thought to have in mind when you stare out across the valley’s broad rumple of hills and feel the hot equatorial breeze on your skin. The human race picked a pretty special place to start out. I’d been finding out that it was a special place to walk, too.

For the past week I’d been travelling by foot across the valley under gaping skies of blue, clocking up the kilometres by day and camping on riverbanks and hilltops at night. This was not the Kenya of high-end savannah lodges and lion sightings, nor was it the Kenya of beach resorts and dhow boats. The bushland was punctuated by corrugated iron churches and mud-and-thatch villages. “Little number of tourists here,” smiled my unflappable local accomplice Jackson one morning, after we’d exchanged long handshakes with a goatherd. “Everyone is happy to see us.” I’d come to western Kenya – around six hours’ drive from Nairobi – to hike the Trans-Rift Trail, a new community-focused project aimed at drawing more visitors to this sweepingly scenic but often overlooked part of the country.

The idea behind the initiative is a simple one: the walking trail passes from one side of the Great Rift Valley to the other. Stitching together old grazing routes and trading paths, it follows a 140km route between the valley’s eastern and western escarpments, tracing a cross-section across the basin floor itself, from ridge to ridge. It makes use of local hiking guides, local food and local campsites. “I see it like a walk back in time,” explained William Kimosop, the trail’s founder and chief game warden of the region. He had a wide grin that made him instantly likeable. “This part of the valley is often called the cradle of mankind, but it was also a magnet for a lot of the great 19th-century explorers, the early pioneers – people like Joseph Thomson, James Hannington and Count Samuel Teleki. They all came here. So you’ll be following in their footsteps too.”

Africa’s best – Formed between 30 and eight million years ago as the planet did its best to rip Africa in two, the Great Rift Valley is an immense fissure stretching 6,000km along the length of the continent, from the Middle East in the north to Mozambique in the south. The feature’s now-familiar name was coined by another Victorian-era traveller, British geologist John Walter Gregory, who came to Kenya twice and was astounded by the sheer size of the trench. He declared it the most beautiful view’ in Africa’. The valley’s shape also means it forms a natural migration corridor for birdlife, so it was fitting that the week began with me looking down onto a pink-hued panorama. It was October, and somewhere in the region of 700,000 flamingos were resident on Lake Bogoria.

I was standing on the rim of the eastern escarpment, above the lake’s silvery alkaline waters. Vast twig-thin flocks of flamingos were clustered in dense numbers around the shoreline, feeding on the blue-green algae that, illogically, gives the birds their rosy tint. As I watched, several hundred of them took flight – ungainly on take-off, then hard and fast when airborne – to a more distant part of the lake. Hot springs and geysers frothed and bubbled along the waterside. Pelicans looked on from high branches. The whole scene had a grand, cinematic quality; I was left marvelling, not for the last time, that there was no one else around – no white jeeps, no frantically snapping tour groups -to savour the view.