It looks like a scene out of fantasy TV series Game of Thrones: a massive wall of unforgiving and apocalyptic white ice.

But as a mammoth cold front blasts North America, temperatures have dropped so low tourists visiting Niagara Falls have been confronted by a giant frozen waterfall.

Niagara Falls freezes over as temperatures in North America plummet. Credit:The Canadian Press

Pictures taken at Horseshoe Falls on Friday show the popular tourist attraction dripping with icicles as a handful of brave souls battle against temperatures as low as -14 degrees celsius.