Close your eyes … and prepare to hear what some people consider the sound of God.
Leigh Ann Henion is a writer from North Carolina who has written a kind of Eat, Pray, Love - next generation.
She's travelled the world to be in the presence of the "phenomenal" -- natural happenings which evoke unbridled wonder.
Her quest for meaning has taken her from the volcanos of Hawaii to the coral reefs of Australia to the northern lights of Sweden.
In Hawaii, she studied the phenomenon of infrasound, low frequency sounds created by volcanoes.