With the rocks that make up the island of Ireland now in place, this is the story of the island’s intricate and intimate relationship with water and ice. At Killary Fjord, the immense bulldozing power of the glaciers which eroded and shaped the island through millenia-long cycles of formidable ice ages can be seen. In Norway, there's a look back through a window in time to see how ice continues to carve and mould the landscape. From Croagh Patrick, there's a spectacular view of the ice-sculpted drumlins of Clew Bay, plus the intriguing ‘raised beaches’ in Donegal which reveal clues of ancient shorelines where the ice retreated into the sea. In Dublin Bay, there's a look at how sea levels were once so low that it may have been possible to walk to Wales.