Television in Scotland 4, and Channel 5, whose broadcast coverage is more limited, and in very remote areas difficult or impossible to receive. Scotland has its own BBC Scotland services, BBC One Scotland and BBC Two Scotland, which commenced broadcasting on 14 March 1952 and 20 April 1964 respectively. Much of the output of BBC Scotland Television, such as news and current affairs programmes, and the Glasgow-based soap opera, "River City", are intended for broadcast within Scotland, whilst others, such as drama and comedy programmes, aim at audiences throughout the UK and further afield. Sports coverage also differs, reflecting the fact that the
Hillforts in Scotland settlement developed in the Hownam model is still seen as having some validity. A. H. A. Hogg identified four types of hillfort: contour forts, promontory forts, cliff forts and ridge forts. Contour forts, where banks and ditches are moulded to the shape of the hill, are the dominant form in Scotland. Less significant are promontory forts, usually employing coastal features, such as the largest one in Scotland at the Mull of Galloway. Different types of defensive style occurred throughout the Iron Age period, some of which may have been a response to Roman siege warfare. There were different combinations in