Hanna Gronkiewicz-Waltz

Launch of the Mayors Challenge...(left to right) Hanna Gronkiewicz-Waltz the mayor of Warsaw, Boris Johnson the Mayor of London, Michael Bloomberg the Mayor of New York and Matteo Renzi the Mayor of Florence at the launch of the Mayors Challenge in Europe at City Hall in London. PRESS ASSOCIATION Photo. Picture date: Tuesday September 24, 2013. The competition invites leaders of European cities to enter with prizes of 5 million Euros for the grand winner. Photo credit should read: Philip Toscano/PA Wire

Philip Toscano/PA

Four mayors – from left, Hanna Gronkiewicz-Waltz of Warsaw, Boris Johnson of London, Michael Bloomberg of New York and Matteo Renzi of Florence – at the launch of the Mayors Challenge in Europe at London’s City Hall. The competition invites European cities to compete for €9m in prizes for ideas to improve urban life. Read more