Journalist Henry Morton Stanley led an expedition between 1874-1877 to map the Lualaba and what other river?

Sir Henry Morton Stanley (1841-1904) was a Welsh journalist and explorer famous for his exploration of central Africa and his search for the missing missionary and explorer David Livingstone. Stanley is also known for his work in the Congo Basin.

In 1874, Stanley set off on an expedition in Africa to trace the course of the Congo River to the sea. After 999 days, Stanley reached the Portuguese outpost of Boma, around 100 km (62 miles) from the mouth of the Congo River. Stanley started with a team of 356 people, but he reached Boma with 114 survivors, of which he was the only European left. He wrote about the trials of the expedition in his book 'Through the Dark Continent'.

During the expedition, Stanley and his men also navigated the Lualaba river up to and beyond the point where it turned westward to join the River Congo.

Stanley's expeditions are unfortunately known for the cruelty and murders of many Africans. He has the highest kill rate among explorers. Despite this, he was admired and supported by the British and Belgian monarchies, and knighted in 1899.