My understanding on Happening is something different. From the movie I perceive that something strange happened and people don't have answers to it. Different people have different explaninations but yet they don't know why it is happenning. These are something beyond human cognition. People do not have even a little clue on why is it happening on them? The good thing about movie is it first gives perception that nature is taking a revenge but not so. No explanantion of why it happened. Something happend but people don't know why !!!!