NIAGARA FALLS, N.Y. (AP) -- The winter's deep freeze has transformed Niagara Falls into an icy spectacle, encasing the trees around it into crystal shells and drawing tourists who are braving below-zero temperatures.

Masses of ice form in the lower Niagara River and around the American Falls as seen from Niagara Falls, Ontario, Canada (AP Photo/The Canadian Press,Aaron Lynett)

The Niagara River keeps flowing below the ice cover, so the falls aren't completely frozen over. But the massive ice buildup near the brink has become a tourist magnet for the second straight year after several relatively mild winters.

Visitors have been flocking to Niagara Falls State Park, next to the American Falls, one of three waterfalls that make up the natural attraction. Days of subzero temperatures have created a thick coating of ice and snow on every surface near the falls, including railings, trees and boulders.

Things aren't expected to thaw out soon: Temperatures dipped to 7 below zero in Niagara Falls on Friday morning.

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