1874-77 are the inclusive dates of Henry Morton Stanley’s transcontinental expedition. This remarkable expedition resolved the major questions surrounding the source of the 
Nile. Stanley circumnavigated Lake Victoria (click for geospatial location), confirming John Hanning Speke’s claim that the Nile exited from its northern shore. He then circumnavigated Lake Tanganyika, disproving speculation that it provided an alternative tributary to the Nile. Finally, he followed the course of the Lualaba river, demonstrating that it flowed into the Congo, which he took to its outlet in the Atlantic. Image: Photograph of Sir Henry Morton Stanley from The Autobiography of Sir Henry Morton Stanley (1890). This image is in the public domain in the United States as its copyright has expired. Note that the exact month of the beginning and end of this expedition is difficult to determine.
BRANCH is an open-access publication 