Tanzania is home to one of the single largest remaining elephant populations in the world. Most of these elephants are found in the remote and wildly beautiful Selous Game Reserve, a World Heritage Site. The name derives from hunter-explorer Frederick Courtenay Selous, a keen naturalist and conservationist as well as a hunter. He was killed in the First World War in the Beho Beho region of the Reserve. Larger than Switzerland in size, the Reserve is the largest in Africa and is second only to the Serengeti in its concentration of wildlife. The Reserve has a varied terrain of rolling savannah woodland, grassland plains and rocky outcrops. Buffalo, crocodile, hippo and wild dog can also be seen here. The Reserve can be reached from Dar-Es-Salam by road, air charter, and rail (Tazara) and the best time to go is in the cool season between the end of June and the end of October. Walking safaris can be taken from the camps in the Reserve, in the company of an armed guard.