Two irrigation systems, Egypt, c 1798.

EGYPT - SEPTEMBER 18: Illustration of the shadouf and the mental, two methods of raising water to irrigate crops which have been in use in Egypt for thousands of years. From �Description de l'Egypte, ou Recueil des observations et des recherches qui ont ete faites en Egypte pendant l'Expedition de l'Armee francaise�, (Paris, 1809-1830). The book, ('Description of Egypt' in English), documents Napoleon's (1769-1821) military and scientific expedition to Egypt in 1798. Baron Dominique Vivant Denon (1747-1825) headed a group of the leading scholars, artists and scientists of the day who accompanied the expedition. (Photo by SSPL/Getty Images)