200km (124 miles) SE of Nairobi

Notoriously remembered as the scene of bloody massacre inflicted by the Hollywood-immortalized man-eating lions of Tsavo, it's hardly surprising that Kenya's largest wildlife preserve isn't the country's most popular destination. Occupying a whopping 3% of the country's land area, Tsavo is comparable in size to Michigan, Jamaica, Wales, or Israel, and large enough to have been split into two separately managed parks -- Tsavo East and Tsavo West -- sadly divided up by the country's busiest highway, an ill-considered deathtrap for animals instinctively roaming between the unfenced reserves. With the constant roar of traffic chasing between Nairobi and Mombasa, were it not for the frequent scenes of roadkill that includes rarely spotted animals, you'd hardly suspect that each of the adjacent parks shelters an overwhelming abundance of wildlife, including a third of Kenya's total elephant population -- just more than 11,000 of the beasts roam this ecosystem. If you have any say in the matter, ask your driver to slow down while driving between Nairobi and Mombasa.

Transformed into a wildlife preserve by pioneering warden David Sheldrick, the arid Tsavo was, until the 1940s, unchartered, completely undeveloped, and known simply as the Taru Desert. As with so many officially protected parks, Tsavo became a protected area because of its unsuitability for agriculture -- a tsetse fly infestation and lack of water kept this great swath of land from human exploitation. Previously, it served as hunting grounds for the Waliangulu and Kamba tribes, and it also saw some Anglo-German conflict during World War I. More recently, its outer extremities and northern reaches have been sites of bitter conflict between poachers and conservationists too ill equipped and understaffed to adequately police such a vast terrain. Nevertheless, authorities claim that they're winning the war on elephant and rhino poachers, and game numbers are on the increase.

There are only two permanent rivers in this vast area. The Tsavo begins its life as snowmelt on Kilimanjaro and is greatly supplemented by a huge underground river flowing toward the famed Mzima Springs, a veritable oasis in Tsavo West. Meanwhile, the Athi River, in Tsavo East, begins near Nairobi. With the exception of small pockets of oasislike vegetation -- doum palms and Tana poplars that line the rivers and shelter the springs -- Tsavo's terrain can be extremely dry, dusty, and inhospitable, its miragelike plains broken by volcanic remnants and immense lava flows. Still, it's a landscape of unusual beauty and distinctive contrasts; the type of vegetation, in fact, varies so markedly that you'll notice distinct changes in the microclimate -- the temperature, even -- as you move around. One minute you might be watching hippos and crocodiles on a wide beach along the river, and the next observing the Tsavo's famous "red elephants" stomping in the dust. And with so much space in which to maneuver, it's not much of a challenge to steer clear of fellow visitors.