With "The Visitors", ABBA took several steps away from the "lighter" pop music they had recorded previously and the album is often regarded as a more complex and mature effort. The opening track, "The Visitors", with its ominous synthesizer sounds and the distinctive lead vocal by Frida, announced a change in musical style. With Benny and Frida going their separate ways, the pain of splitting up was explored yet again in "When All Is Said and Done". The major hit single on the album, "One of Us", also depicted the end of a love story. Elsewhere there were Cold War themes—highly topical at the time—and further songs of isolation and regret.