During the 1960s and 1970s, the city gained a reputation as an important center for liberal politics. Ann Arbor also became a locus for left-wing activism and served as a hub for the civil-rights movement and anti-Vietnam War movement, as well as the student movement. The first major meetings of the national left-wing campus group Students for a Democratic Society took place in Ann Arbor in 1960; in 1965, the city was home to the first U.S. teach-in against the Vietnam War. During the ensuing 15 years, many countercultural and New Left enterprises sprang up and developed large constituencies within the city. These influences washed into municipal politics during the early and mid-1970s when three members of the Human Rights Party (HRP) won city council seats on the strength of the student vote. During their time on the council, HRP representatives fought for measures including pioneering antidiscrimination ordinances, measures decriminalizing marijuana possession, and a rent-control ordinance; many of these remain in effect in modified form. Alongside these liberal and left-wing efforts, a small group of conservative institutions were born in Ann Arbor. These include Word of God (established in 1967), a charismatic inter-denominational movement; and the Thomas More Law Center (established in 1999), a religious-conservative advocacy group.

Answer this question, if possible (if impossible, reply "unanswerable"): In 1956, Ann Arbor was home to the first U.S. teach-in against what war?
unanswerable