St Breock Downs Monolith2013-04-12 · Free entry Originally 5 metres (16 feet) high and weighing some 16.75 tonnes, this is Cornwall's largest and heaviest prehistoric monolith. It stands on the summit of St Breock Downs, offering wonderful views.How to find usSt Breock Downs MonolithRosenannon CornwallVisit the attraction’s website ↗Get directions ↗