In the first episode, Ifor explores why ruins are among the best-preserved and most-loved holy sites in Britain. He visits the famous ruins of St Andrews Cathedral, the mystical atmosphere of Wales's best-preserved Roman site, the battered remains of Coventry's iconic cathedral and the Gothic majesty of North Yorkshire's Whitby Abbey - the inspiration behind Bram Stoker's Dracula. Along the way, he asks why we're drawn to holy ruins long after their religious use is over.

In the second episode, Ifor explores why water crops up again and again as the essential element in many of our most holy places. Why has a yearning for pure natural water always been bound up with our spiritual beliefs? His journey takes him to our oldest mass baptismal pool which marks the place that Scottish Picts first came into the Christian fold, the site on Loch Ness where Celtic missionaries battling the forces of paganism first encountered the legendary monster, a healing well where a young woman was reputedly brought back to life by having her severed head re-attached to her body, and a 2,000-year-old holy spring that has become a major international brand.

Ifor visits trees and mountains as a way of understanding the journey Britain undertook from the old Pagan religion to Christianity. His journey starts in Glastonbury, site of the famous tor and the Thorns, the most holy trees in the country. He discovers how even now these symbols are causing friction and discord. His journey continues at Knowlton in Dorset, a place where a Norman church has been built right in the centre of an earthen henge. There he meets a druid who explains how Pagan sites were often overwritten in this way by the new Christian religion before they both discover that, at least here, earth magic seems to be making a comeback. Ifor visits a bleeding yew tree that has divided opinion for 600 years, and in Snowdonia a mountain where the devil is said to have gone toe to toe with an early Christian missionary.

Ifor sets out to understand the appeal of shrines. For those outside the Catholic and Orthodox church there is something vaguely unsettling about shrines. How can venerating the bones of a dead person bring you closer to God?

From the unlikely starting point of Marc Bolan's roadside shrine in Barnes, Ifor embarks upon perhaps his most surprising journey. Along the way he learns that Scotland's largest city only exists because of a shrine and visits the newly-renovated shrine of St David in Wales.

At St Albans Cathedral, he learns that shrines are slowly but surely starting to creep back into the Anglican mainstream and that rather than meeting resistance, they are being actively embraced. After viewing a genuinely shocking relic in Westminster Cathedral, Ifor meets with the Catholic archbishop Vincent Nichols, who has a radical theory about how the return of shrines represents the final chapter of the Reformation, and that is all down to Princess Diana.

Ifor sets out to understand the appeal of islands as holy retreats. It may seem obvious that we would feel closer to the divine when surrounded by the stunning natural beauty of an island, but Ifor soon discovers there is a far deeper reason they became such a major aspect of religion.

His journey takes him from the Lake District to the Mappa Mundi in Hereford Cathedral, from our most famous holy island at Lindisfarne to the Western Isles in Scotland where an ancient Christian holy island has been reborn as a Buddhist monastery. He visits the island where the Welsh version of St Valentine lived and finally heads out west to the barren island of Bardsey, at the very furthest tip of Wales. This is known as the Island of 20,000 Saints, a place that exists halfway between this world and the next.

Ifor sets out to understand what happens when our religious urges drive us underground. His first stop is Lud's Church in Derbyshire, one of the most dramatic and eerie holy places in the land, once described as 'the place for the Devil to say matins'. Ifor then heads back 14,000 years to find evidence of perhaps the oldest holy place in Britain. He follows the path of St Cuthbert's body as it was shifted between caves in the north of England to escape the attentions of Viking raiders and visits the cave of St Govan where a hermit was miraculously enveloped in rock to evade local gangs of wreckers. He meets a nun in Norwich who tells him about a young woman who was bricked up alive for over 40 years in an act of almost unbelievable devotion and finally heads to a crypt of Ripon Cathedral to discover one of the most dramatic pieces of religious theatre in Britain.