David Conrads in The Christian Science Monitor:
It was a geographical mystery that had befuddled explorers, astronomers, and philosophers for two millennia: Where did the Nile begin? In “River of the Gods: Genius, Courage, and Betrayal in the Search for the Source of the Nile,” historian Candice Millard recounts the adventures of two ambitious, Victorian-era rivals who spent years trekking through East Africa, enduring unimaginable hardships, in an effort to be the first to solve the puzzle.
European fascination with Egypt and the Middle East was sparked by the discovery of the Rosetta Stone in 1799 and its deciphering 23 years later. While 19th-century explorers were scattered across the globe, filling in the map of the world, none had been able to locate the headwaters of the White Nile, the longest branch of the longest river in the world. The question of where the Nile began constituted, in Millard’s words, “the Holy Grail of exploration.”
Eager to seize the grail was Richard Francis Burton, a British explorer, scholar, linguist, and adventurer. Fluent in Arabic, as well as 24 other languages and 12 dialects, he disguised himself as a Muslim pilgrim and became the first Englishman to travel to Mecca, which was forbidden to non-Muslims, in 1853. The next year the newly formed Royal Geographical Society in London chose him to locate the headwaters of the Nile.
More here.