Exploring ice caves on Lake Superior, 3 of 5 Great Lakes are completely frozen over

Image caption: "Edward Mitchell, front, of Detroit, and James Kuhn, of Seattle, explore an ice cave at the Apostle Islands National Lakeshore on Lake Superior," AP

"Three of the five Great Lakes had completely frozen over by Thursday." Image caption, Lake Michigan, Xinhua

2/27/15, "Battle to keep the Hudson open: Ice breakers sent out in New York big freeze as hundreds flock to see ice caves opened by perfect winter conditions," UK Daily Mail, Wills Robinson 

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