It looks like scenes from a past Ice Age but these photos were actually taken in frozen sandstone caves - some of which can only be accessed by hiking across a frozen lake. Photographer Ian Plant celebrated his birthday by enduring the cold and dangers of a three-mile hike across the frozen surface of Lake Superior, in Wisconsin, USA, to visit these spectacular natural displays.
It was the first time in five years that the caves have been accessible by hiking across the frozen lake. The mainland ice caves, which can also be seen in the spectacular photo set, are found along cliffs in the Apostle Islands National Lakeshore, in Wisconsin, USA. SEE OUR COPY FOR DETAILS.
Pictured: The ice cave - Icicles hang from the cave.