Germany, the biggest and richest country in the European Union, is going through a period of considerable political turbulence. After Chancellor Angela Merkel's party, the CDU, performed badly in state elections, she said she would not seek re-election. Much has been said about the threat posed to her party from the right by the emergence of the Euro-sceptic anti-immigrant AfD. But there's another emerging force - the internationalist and environmentalist Greens. In the recent elections in both Bavaria and Hesse, the Greens came second with a big gain in seats - and polls now have the party polling in second place nationally. Paul Henley and a panel of experts discuss what's behind the rise of the Greens and what it means for the country at the heart of Europe.