Now, in an inspiring film, we probe the secrets of Niagara Falls. From helicopter and speedboat, at high-tech labs and at rope's end, we join earth scientists as they struggle to piece together the epic life story of North America's most celebrated natural wonder. We experience the Falls that daredevils and stunters could never tame -- the Niagara that is a vertical battleground between water and rock. Most think of it as a vision eternal, but in fact, Niagara's life has been a geological blink of the eye. Only a hundred and twenty five centuries ago it was unleashed, born of the last glacial surge that swept the continent. Since then, it has traveled more than seven miles upriver, cutting the Earth's crust like a knife. Its relentless procession has granted scientists a breathtaking window into the past.