Freezing temperatures have created the perfect conditions to visit Wisconsin's Apostle Islands caves, accessed by walking a mile out onto a iced-over Lake Superior. For the first time in five years, visitors are able to explore the island's caves which have been turned into a 'fairyland of needle-like icicles' thanks to that polar vortex. The caves are a popular destination during the summer when they can be accessed by kayak, but they're even more of a draw during winter when as many as 1,000 people a day make the trip on the weekend.'The formations we are seeing this year are some of the best I've ever seen,' Neil Howk, assistant chief of interpretation with the Apostle Islands National Lakeshore, told WDIO. 'People love coming out here in the summer because the cliffs and the caves are just beautiful, but this time of year...it's incredible,' Mr Howk added.'For most people, walking on a frozen Great Lake is just a remarkable experience psychologically, let alone physically,' park superintendent Bob Krumanaker told Wisconsin Public Radio. 'It's pretty solid generally and depending on the visibility it could be as white as far as you can see. But you know the lake is under it and sometimes you can even feel the ice move a  little bit.' Krumanaker describes the interior of the caves, saying they are covered with what looks to be beautiful rock formations but in reality is stalactites and stalagmites made entire of ice.'And then if you carefully crawl under some of that ... the ice is completely smooth and generally completely clear underneath it. So, it’s like there’s a glass floor that you can see the bottom of the lake,' he said.The caves are located 18 miles west of Bayfield, Wisconsin. Krumanaker hopes they'll be open for another six weeks, but conditions could make them unreachable soon. To see if the caves are open, call 715-779-3397 ext 3.(dailymail.co.uk)ANN.Az