Modern buildings and a new road layout in the Iraqi city of Erbil. Erbil is home to the Citadel of Arbil, an inhabited mound in the centre of the modern city which is said to be one of the oldest, continually inhabited places in the world. Earliest traces of habitation on the mound date back to the 5th millennium BC, possibly earlier. The city of Erbil, the fourth biggest in Iraq, is today the capital of Iraqi Kurdistan. .Since 2007 the High Commission for Erbil Citadel Revitalisation (HCECR) has been in charge of the Citadel complex and is carrying out major reconstruction efforts since moving out all remaining residents. It is hoped that 50 families will move back into the Citadel once renovation work and archeological digs have been completed. .