This year we celebrate fifteen years of the Formentera Half Marathon and we want to celebrate it with all of you in a special way. For this reason, on Friday the 10th at 11:30 p.m., in the Plaça d'Espanya in the town of Es Pujols you will be able to enjoy a free concert by 'Efecto Mariposa', a reference group in national pop/rock of recent years, with songs as well-known as 'Por Quererte', which was number one in 2009 and chosen best song of that year at the 40 Principales Awards. Since its birth and until today, the band has currently been reduced to the duo formed by two of its founders, Susana Alva, singer, and Frasco G. Ridgway. Its rhythm and lyrics will help us set the tone for the preview of the Formentera Half Marathon and the 8K San Ferran-La Savina