One of the perks of winter is being able to walk across frozen lakes. But usually the frozen top of the lake appears white. Tomas N and his buddy were hiking in Slovakia when they stumbled upon a rare gem of nature. A frozen mountain lake in High Tatras Mountains was so crystal clean, it appeared perfectly clear when frozen. It looks like they are walking on air! It’s no wonder this video has instantly gone viral with over half a million hits and counting!