The explorer known for his journey along the Nile River is John Hanning Speke. He was an English explorer of the 19th century, famous for his explorations of East Africa and his search for the sources of the Nile River. Speke, along with fellow explorer Richard Burton, undertook expeditions that aimed to uncover the origins of this major waterway, which had been a subject of intense interest and speculation among European explorers. Speke's discovery of Lake Victoria in 1858 was significant as it was identified as one of the sources of the Nile. His explorations contributed to the understanding of African geography and colonial interests.