What do you do when you stumble across a crystal-clear lake, in which you could see clear to the bottom, plus on top of being crystal clear, it’s also completely frozen?

This YouTube video shows  Thomas Nunuk and his friend walking carefully across what appears to be the surface of a frozen lake in Slovakia.  The water is so clear that every rock is visible underfoot.

If you are wondering how this is possible, scientists say that it’s  only possible when the temperatures fall from being relatively mild to very cold very quickly.  Plus at the same time, the weather has to be clear with no snow which tends to make the ice cloudy.

This looks so cool, but so freaky at the same time