 Complete the following phrase:  The period or the late 1960  1970s came to be known as the Opposti Estremismi, from left-wing and right-wing extremists riots, later renamed anni di piombo years of lead because of a wave of bombings and shootings  the first victim of this period was Antonio Annarumma, a policeman, killed on 12 November 1969 in Milan during a left-wing demonstration. In December 1969, four bombings struck in Rome the Monument of Vittorio Emanuele II Altare della Patria, the Banca Nazionale del Lavoro, and in Milan the Banca Commerciale and the Banca Nazionale dellAgricoltura. The later bombing, known as the 