At almost 22,000 square kilometres, Tsavo is Kenya’s largest national park. It is comprised of two separate parks – East and West – divided by the railway from Mombasa to Kenya’s interior. They are two distinct ecosystems: Tsavo East is generally flat, with dry, undulating plains crossed by the Galana River; Tsavo West is more mountainous and is wetter than its counterpart, with swamps and wooded hills. This unspoilt wilderness can be traversed for hours without seeing another traveller, but wildlife is abundant. Resident species include lions, leopards, crocodiles, buffalo, pods of hippos and vast herds of elephants. Birdlife is also plentiful, with more than 500 species including the martial eagle, vulturine guineafowl and the secretary bird.