Excalibur marathon, half marathon and 10K are run over the Clwydian hills range in North East Wales.
http://www.conquerexcalibur.org.uk/
‘Excalibur is the tough trail event that traverses the spectacular Clwydian Range of North Wales. With over 5,500 feet of steep ascent in the marathon route, Excalibur will take you to the edge. Excalibur tests the limits of each and every person who attempts to conquer it. Both fitness and mental courage are needed to complete this challenge. Do you have what it takes?’
