An estimated 7,000 Czechoslovaks defy a travel ban to attend a conference on Central Europe at Wrocław University in Poland, where they hear Polish dissident-turned-senator Adam Michnik apologize for Poland's role in the 1968 Warsaw Pact invasion of Czechoslovakia. Havel is refused a passport to attend the conference, but his featured speech is read out in his absence. Participants sign a protest to Prague calling for liberalization and denouncing 'the arrest of friends who had only come to wonder about what binds and unites Central European societies.'