Following the implementation on 1 January 2011 of the Kallikratis Plan, the administrative divisions of Greece consist of two main levels: the regions and the municipalities. In addition, a number of decentralized administrations overseeing the regions exist as part of the Ministry of the Interior, but are not entities of local government. The old prefectures were either abolished and split up or transformed into regional units in 2011. The Autonomous Monastic State of the Holy Mountain is an autonomous self-governing entity.