Monty Don visits the world's 80 most inspiring gardens: this time, in Northern Europe. Monty is spoiled for choice in an area he knows so well. He views the floral wonders of Britain's Sissinghurst Castle and the vivid palette of impressionist painter Monet at Giverny. He enjoys the quirky individuality of the garden of one of his favourite Belgian designers. Finally, Monty goes to Norway to see what can grow 200 miles north of the Arctic Circle.