This weekend on the iHeartRadio Countdown With Mario Lopez we're finishing up our top 40 songs of 2019 countdown with the top 20! What was your favorite song of 2019? Tweet us @ONWithMario! Mario's favorite jam of 2019 was Panic! At The Disco's 'High Hopes' which may just be the #1 song of the year! Tune in this weekend to find out.