Maasai Mara National Reserve

Where it sits. The Maasai Mara covers about 1,510 km² of rolling grassland in Narok County, in Kenya's south-west, running to the Tanzanian border where it joins the Serengeti without a fence. The land lies between roughly 1,500 and 2,180 metres, high enough that mornings are cold and the light is hard. The Siria escarpment, also called the Oloololo, forms a wall along the western edge and drops onto the flat, lightly wooded Mara Triangle. The Mara River, fed by the Talek and the Sand, cuts through the reserve in a deep, muddy channel lined with fig and croton — the single feature that governs both the wildlife and the tourism calendar.

The story behind it. Protection began in 1961 with a 520 km² wildlife sanctuary covering the triangle, expanded the same year to 1,821 km² and converted to a game reserve under the Narok County Council. Part of it was upgraded to national reserve status in 1974, land was returned to communities in the same period, and further excisions brought it down to its present size by 1984. The Maasai who had grazed the area were moved out to create it, a history that shapes current arrangements: the reserve is not managed by the national wildlife service but by county government, with the Mara Triangle run since the early 2000s by the not-for-profit Mara Conservancy, which enforces off-road driving rules far more strictly than the eastern sector. Around the reserve, a ring of community conservancies — Naboisho, Olare Motorogi, Mara North and others — lease grazing land from Maasai families and cap vehicle and bed numbers, and they now hold a substantial share of the ecosystem's wildlife.

The migration. Between roughly July and October, depending entirely on rainfall, some 1.3 million blue wildebeest move north out of the Serengeti with around 200,000 zebra and several hundred thousand Thomson's gazelle, on a clockwise circuit of roughly 800 kilometres. The river crossings that draw the crowds are concentrated at a handful of known points where the banks are climbable; herds mass for hours, then commit in a rush, and Nile crocodiles that have waited all year take what they can. It is a violent, chaotic, deeply unphotogenic scramble that nonetheless produces the footage everyone recognises. Timing cannot be booked in advance with any confidence — the herds respond to grass and storms, not to calendars.

On screen. More natural-history film has come out of the Mara than almost any other savanna. The BBC's Big Cat Diary, first broadcast on BBC One in 1996 and developed by Keith Scholey, ran for eight series and turned specific animals into recurring characters, following lions of the marsh pride and their neighbours across the Musiara marsh, Leopard Gorge, Fig Tree Ridge and the Mara River; the strand ended with the live Big Cat Live transmission from the reserve in 2008. Disneynature's African Cats (2011) was filmed here over more than two years. The consequence for visitors is unusual: the terrain is genuinely familiar before you arrive, and guides will name the lineage of a pride going back two decades because the cameras documented it.

What a day looks like. Drives run at first light and again from late afternoon, with the middle of the day spent in camp because the cats are flat under bushes. Balloon flights lift from the Musiara and Talek areas at dawn and land to a breakfast on the grass. Beyond the migration, the reserve holds one of Africa's highest densities of lion, plus leopard along the watercourses, cheetah on the open plains east of the Talek, elephant, buffalo, topi, giraffe and a small, closely guarded black rhino population. Vehicle crowding at crossings and sightings is a real problem in the eastern sector in peak season; the triangle and the conservancies are the practical answer. Crossing between the two halves means the bridge at Purungat in the south or Mara Bridge on the western side, both of which add an hour or more to a drive, so most camps work one sector only.

Getting there and timing. The road from Nairobi runs about 270 km and takes five to six hours, the final stretch rough enough to shake fillings loose; scheduled light aircraft reach the Musiara, Ol Kiombo and Keekorok airstrips in 45 minutes. July to October covers the migration at premium prices. January to March is dry, quiet and excellent for cats. The long rains in April and May close some camps and make black cotton tracks impassable, though the country is at its greenest. Nights drop into single figures, so warm clothing for early drives matters more than most people expect.