"Chinese" Gordon, the man who led the mercenary army that defeated the Taiping Rebellion on the Yangtze River in China and whose death at Khartoum on the Nile River helped spark the Mahdist War in the Sudan.
I recall a haunting passage from his journals from the mid 1870s when he was chasing slavers in Darfur Province. Riding at night, he kept seeing curious round stones at intervals along side the trail. As dawn came, he realized the "stones" were children's skulls, from the children who could not keep up with the slave coffles and who were then left to die in the desert.