VICTORIA FALLS, ZIMBABWE - MARCH 17: A rainbow forms as the Zambezi River plunges 420 feet March 17, 2008 at Victoria Falls, Zimbabwe. Considered one of the world's seven natural wonders, Victoria Falls stretches some 2,000 yards, forming the world's largest waterfall. The spectacle continues to draw thousands of tourists every year, injecting a much needed dose of foreign currency into the local economy. (Photo by John Moore/Getty Images)