The songs of Imants Kalniņš were best known as performed by the Menuets group which only played songs by this composer. Most of the members of the group moved on to form another group, Pērkons ('Thunder') later. Pērkons was a symbol of rebellion. They played fascinating rock and roll bordering on hard rock music, composed by band's leader Juris Kulakovs, using poems mostly written by Māris Melgalvs. Many of those were strongly disapproved by the Soviet authorities, as they implied the ridiculousness of the system. The most famous concert by Pērkons resulted in the destruction of a train compartment by the young people who had attended the concert. This, as well as other events, is portrayed in the movie Is It Easy to Be Young? by Juris Podnieks. Acts such as Pērkons certainly played an important role in the lives of the youth of the time and were a serious challenge to the Soviet system.