In cultures that traditionally or currently use calendars other than the Gregorian, New Year's Day is often also an important celebration. Some countries concurrently use Gregorian and another calendar. New Year's Day in the alternative calendar attracts alternative celebrations of that new year: African SEP 11 37 Fri Nayrouz and Enkutatash are the New Year's Days of the Coptic Egyptians and the Ethiopians, respectively. Between 1900 and 2100, both occur on 11 September in most years and on 12 September in the years before Gregorian leap years . They preserve the legacy of the ancient Egyptian new year Wepet Renpet, which originally marked the onset of the Nile flood but which wandered through the seasons until the introduction of leap years to the traditional calendar by Augustus in 30-20 BC. In Ethiopia, the new year is held to mark the end of the summer rainy season . JUN 14 24...