Standing under the waterfall, the left brain is forcibly silenced. There is no room for thoughts; you are forced to be entirely in the present moment.
If you focus on the fear of falling rocks, or the urge to escape the freezing cold, it becomes impossible to endure the heavy flow. You have no choice but to surrender, creating a state of absolute "nothingness" (Mu).
Only through this emptiness do you truly realize your connection to nature and the Earth. And eventually, you can even feel a connection to the universe itself.
(Note: The people in the photo are wearing traditional white garments for this sacred purification ritual.)