The 2015 Spanish local elections were held on Sunday, 24 May 2015, to elect all 67,515 councillors in the 8,122 municipalities of Spain and all 1,040 seats in 38 provincial deputations. The elections were held simultaneously with regional elections in thirteen autonomous communities, as well as elections in the three foral deputations of the Basque Country, the four island councils in the Balearic Islands and the seven island cabildos in the Canary Islands. Electoral system Background After Podemos' success in the 2014 European Parliament election, the party decided not to directly contest the local elections scheduled for May 2015 to focus on the regional and general elections to be held throughout that year. Instead, they opted for the Guanyem Barcelona formula, popular unity municipal candidacies comprising different parties and social movements. The model was reproduced in many cities under the name Ganemos (Let's Win). United Left (IU), the traditional left-wing third party of Spain, also started debating whether to join these local coalitions. However, this option was not well received by some party sectors, particularly their Madrid branch, who feared that the party would lose its identity if it joined these coalitions. The first attempt at a joint candidacy that included Podemos and United Left, among others, succeeded in Barcelona with Guanyem Barcelona, later Barcelona en Comú, under activist Ada Colau's leadership. Another national party that decided to participate in most of these unitary candidacies was Equo, as well as minoritary parties like For a Fairer World (PUM+J), Building the Left–Socialist Alternative (CLI–AS), Republican Alternative (ALTER), Renewal–Nationalist Brotherhood (Anova), or Initiative for Catalonia Greens (ICV). The unitary lists also included individuals from social movements like the anti-eviction PAH, 15M, o the so-called mareas (Spanish for "tides") made up of workers from different service sectors like teachers, Public Health System workers or young people forced to migrate as a consequence of the 2008–15 Spanish financial crisis. Municipal elections Municipalities in Spain were local corporations with independent legal personality. They had a governing body, the municipal council or corporation, composed of the mayor, the government council and the elected plenary assembly. Elections to the local councils in Spain were fixed for the fourth Sunday of May every four years. Voting for the local assemblies was on the basis of universal suffrage, which comprised all nationals over 18 years of age, registered and residing in the corresponding municipality and in full enjoyment of