Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Helwan, also spelled Hilwan or Hulwan or Holwan, is a city in Egypt on the bank of the Nile river, opposite the ruins of Memphis. Originally a southern suburb of Cairo, it served as the capital of the now defunct Helwan Governorate from April 2008 to April 2011, after which it was re-incorporated into the Cairo Governorate. The kism of Helwan had a population of 643,327 at the 2006 population census. The Khedivial Astronomical Observatory was built here 1903-1904, and was used to observe Halley's comet. Egypt's oldest and largest private psychiatric clinic, the Behman Hospital, was also constructed here in 1939.