Mama Mia! It’s hard to believe, but LOT’s 787 fleet has now carried more than half a million people. And to celebrate, the airline had some fun with a very unsuspecting passenger. As the 500,000th passenger checked in for his flight, a flash mob performed songs from the musical “Mamma Mia!” right in the middle of Warsaw Chopin Airport. Whether you’re a fan of ABBA or not, the video below is a must-see.