From the Icefields Parkway - Canada's most scenic driving route - their monumental work is displayed in ever-larger peaks, rising like ruined castles on either side of the road.

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The Icefields Parkway that stretches from Lake Louise to the south and Jasper at the northern end has towering peaks, tumbling unspoiled rivers, massive sheets of glacial ice flowing down the valley to meet the road, and hanging above in the rafters of the peaks.

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As we venture down the extraordinary Icefields Parkway in vans with our super-active, super-attentive guides, Dani Houston, Felicia Perricelli and Andrea McLeod, (pluck is their natural personality) the huge cascading walls of rock we pass look to have the remains of ancient mountain top cities.

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