Parallel Lines is the third studio album by American rock band Blondie, released on September 23, 1978, by Chrysalis Records to international commercial success. The album reached No. 1 in the United Kingdom in February 1979 and proved to be the band's commercial breakthrough in the United States, where it reached No. 6 in April 1979. In Billboard magazine, Parallel Lines was listed at No. 9 in the top pop albums year-end chart of 1979. The album spawned several successful singles, notably the international hit "Heart of Glass".