Sibiloi sits on the eastern shore of Lake Turkana, which is one of the most remote places in Kenya, and getting there is an expedition rather than a day ride. The park was created to protect fossils. This stretch of shoreline, around Koobi Fora, has produced some of the world's richest finds of early human ancestors, from about two million years ago, and teams led by Richard Leakey, Meave Leakey and their colleagues dug here for decades. Petrified trees lie scattered across a fossil forest in the dry ground, and bones of ancient crocodile and hippo turn up in the sediment. It is a place where the story of humankind is lying in the dirt, and it still feels raw.
The lake itself is vast, long and narrow, filling a trough of the Rift Valley, and the water is salty and often green or jade in colour. Wind blows hard here, steady and warm, and the east shore is a hard, hot, volcanic landscape of black stones and thin scrub. Temperatures are high through most of the year, and the nights are not much cooler. Water is scarce and the wind tires everyone out.
Reaching the park is a serious undertaking. Roads from the south run through Marsabit and the stony Chalbi Desert toward Loiyangalani, and beyond there the tracks are rough, corrugated and sometimes sand. Most travellers go by four-wheel drive with a guide, and a motorcycle should be a proper adventure bike with a support vehicle. Security conditions in northern Kenya can change, so check recent advice before going.
Those who make it are rewarded with silence, space and a feeling of having reached the edge of something. Turkana people herd goats and camels along the shore, fish from small boats, and live with the heat in ways that are worth observing quietly. Early morning and the hour before sunset give the best light on the water. The cooler months from June to September are a little kinder.