Arnarhóll hill Before 1764, Reykjavík had no prison to speak of. Convicts were shipped to Copenhagen for imprisonment, at immense cost. In 1757, the Icelandic Sheriffs asked the Danish king permission to hang convicts instead of sending them abroad, since it would save substantial amount of money! The king refused and ordered Icelanders to build a proper prison instead. It was built on Arnarhóll hill.