Educating Humanity has reported on this story extensively, you will find a synopsis of it in the Top 18 Worldwide Mass UFO Sightings page and a much more detailed report in a post titled Children in Africa see UFO and aliens. This report includes Dr. Macks interview with the teachers and children. The video below is well put together and informative, I think you will enjoy it.
Actual drawing by one of the children
On 14th September, 1994, a UFO streaked across the sky over Southern Africa. Two days later, something landed in a schoolyard in Ruwa, Zimbabwe, with three or four things beside it, according to journalist Cynthia Hind. This was witnessed by 62 schoolchildren, who had little or no exposure to TV or popular press accounts of UFOs. Cynthia Hind interviewed them the day after the encounter and made them draw pictures of what they had seen. A few months later, Dr John Mack and research associate Dominique Callimanopulos traveled to Zimbabwe to research one of the most extraordinary group sightings of a UFO in recent times.
At the Ariel School in Ruwa, Zimbabwe, 60 children reported seeing a landed UFO during recess. In 2007, Dominique Callimanopulos and Randall Nickerson began production of an edited video program presenting John Mack’s interviews with the schoolchildren and faculty. The film became a consuming passion of Nickerson’s, and he spent 9 months in Africa to broaden the scope of the film far beyond our initial expectations, discovering new witnesses that corroborate the students’ accounts. He is now editing, after returning from a follow-up visit to Africa in 2009, and visits with the now-adult children in 2010.