2/2 The hunt to solve the mystery behind one of the defining moments in Scotland's history. (R)
Carl Linnaeus and a revolutionary grammar for plants.
BBC Radio 4 FM only
2/4 Footage of a youthful Phil Coulter and the day the American President visited. (R)
BBC Two Northern Ireland only
3/6 How trees and mountains show the journey Britain took from Paganism to Christianity. (R)
1/4 Cormac Ó hÁdhmaill explores the history of Ulster. (R)