We're at the National Library of Latvia in the capital, Riga, for the third of our series of debates across Europe. Questions on the challenges and opportunies ahead for this northern European Baltic state - which lies on the EU's border with northern Russia - are answered by a panel of Latvian politicians and thinkers: Nils Ušakovs, the ethnic-Russian mayor of Riga; Ojārs Ēriks Kalniņš, chair of the Foreign Affairs Committee in parliament; and Baiba Rubesa, chair of the new Rail Baltica project, intended to link the Baltic states to the European rail network. They are joined by Magnus Christiansson, a Swedish security strategist specialising in NATO and the Baltic states. Questions come from the audience in Riga, and also BBC World Service social media followers.