Talking points

The Schirn Kunsthalle museum in Frankfurt, Germany, launches a Yoko Ono retrospective to mark the artist's 80th birthday. The exhibition features characteristic works, using a variety of media, from the past 60 years. Ono became well known in the early 1960s in New York and then in Japan. The exhibition takes a close look at her works from the sixties and seventies, including her influence on concept and performance art, film, music and her work for peace.

Finance ministers and central bankers of the Group of 20, the world's most powerful advanced and emerging economies, meet in Moscow for two days of discussions, which economists expect to focus on the growing risk of a currency war. Both Japan and the United States have been criticised for policies seen as intended to stimulate their economies further - and weaken their currencies in the process.