Complex sentence: In addition to topping the U.S. country charts for five weeks, the song also reached No.3 on the "Billboard" Pop Chart and topped the charts in several countries around the globe, an unprecedented achievement at the time.
Split into simpler sentences: In addition to topping the U.S. country charts for five weeks, the song reached No.3 on the "Billboard" Pop Chart. It also topped the charts in several countries around the globe, an unprecedented achievement at the time.