In 2015 Milan hosted the Universal Exposition; the themes were technology, innovation, culture and traditions concerning food. Participants in the Expo included 145 countries, three international organisations, several civil society organisations, several corporations and non-governmental organizations. The participants were hosted inside individual or grouped pavilions. In June 2010 Sala was appointed CEO of the Expo, which led to the nickname "Mr. Expo" in the following years. The opening of the Expo on 1 May 2015 was marred by protest from anti-austerity activists, black bloc, and anarchists which caused criminal damage, resulting in the police using tear gas. Expo also created some tensions with the Holy See and the Italian government; in fact Pope Francis condemned the concept of Expo, saying that it "obeys the culture of waste and does not contribute to a model of equitable and sustainable development". As Vatican City invested €3 million to obtain its own pavilion at the event before his appointment to the papacy, Francis said that, although it is a good thing that the Church is involved in causes that battle hunger and promote cleaner energy, he stated that too much money was wasted on the Expo itself by Vatican City.
Political career
Mayor of Milan
On 22 March 2015, the incumbent mayor of Milan, Giuliano Pisapia, announced that he had chosen not to run for re-election in 2016 for a second term in office. Following Pisapia's decision, the ruling center-left coalition decided to call an open primary election to choose a new single mayoral candidate. Sala and three other people registered to be candidates in this election. The other candidates were Francesca Balzani, the then deputy mayor of Milan, responsible for the Budget in Milan's municipal government and a former Member of the European Parliament; Pierfrancesco Majorino, then responsible for Social Equalities in the municipal government of Milan; and Antonio Iannetta, the former president of UISP. The election took place on 6–7 February 2016 and Sala won with 25,600 and 42.3% of the vote. On 5 June, in the first round of the municipal election Sala gained 41.7% of first votes; on 19 June, in the second round, he defeated the centre-right candidate Stefano Parisi with 51.7% against 48.3%. On 16 December 2016 Sala suspended himself from office after learning that he was named in an investigation regarding the Expo 2015. He then retired that suspension a few days later.
