The second deadliest war in human history, lasting 14 years in 19th century China with no photographic documentation despite occurring during the early photography era
"The Taiping Rebellion happened right around the time that western wars were just starting to be photographically documented. It was arguably the defining event of the 19th century, lasting for 14 years, a deadlier war than WW1, something like 1 in 10 Chinese people perished."