John Hanning Speke was a British explorer born in 1827, known for his expeditions in East Africa. He is most famous for his search for the source of the Nile River, which he believed to be one of the lakes in the region. Speke's explorations contributed significantly to the understanding of Africa's geography during the 19th century. In 1858, Speke traveled with fellow explorer Richard Burton on an expedition to Lake Tanganyika. Later, he returned to Africa alone and discovered Lake Victoria, which he identified as the source of the Nile. His findings were controversial, but they played a crucial role in the exploration of Africa.