Cadw is also offering a 20% discount on membership, which offers unlimited access to over 100 historical sites from as little as £1.50 a month.
Mae Cadw hefyd yn cynnig gostyngiad o 20% ar aelodaeth, sy'n cynnig mynediad diddiwedd i dros 100 o safleoedd hanesyddol am gyn lleied â £1.50 y mis.