Researchers say an ancient calendar discovered in southern Turkey may also memorialize a devastating comet strike that hit Earth nearly 13,000 years ago.
Why do we have leap years, and what are we supposed to do — or not do — with our rare extra day? NPR's Morning Edition spoke with experts in astronomy, history and economics to find out.
The rare palindrome date also coincides with National Margarita Day in the U.S. Wedding venues, airlines, hotels, and fast-food chains are among those marking "Twosday" with limited-time deals.