In the United States, the song is an airplay favorite today on Adult Standards and Easy Listening radio. 'Eres tú' became one of the only Spanish language songs to reach the top 10 in the United States, peaking at #9 in the Billboard Hot 100 chart and also reaching the top 10 on the Adult Contemporary chart. The group was now on its way to making a remarkable string of hits, most notably 'Eres tú ' ('You are.'), runner up in 1973 and the next year a massive hit in Europe and the United States of America. It was with this configuration of six (three Uranga siblings, Zubiaga, Garay and Ipiña), known in Spain as 'The Six Historic Ones', that Mocedades achieved its greatest successes. Estíbaliz Uranga and the Blanco brothers followed in 1971, and in 1972 Ipiña returned and Carlos Zubiaga (from Los Mitos) joined. Javier Garay who had previously belonged to Voces y Guitarras rejoined the group in 1970 after serving in the Spanish military in Africa. In 1970, both Ipiña (for military service) and Panera (to become a professor at a local university) left Mocedades. He took an immediate interest in the group and renamed them Mocedades, meaning 'youths,' from the Spanish word mocedad, which means 'youth.' Javier Garay could not join them because of his military service, and so Mocedades started out as an eight-member group. They spent a year performing around their hometown before sending a demo cassette to producer Juan Carlos Calderón in Madrid. The members of Voces y guitarras were Amaya Uranga, Izaskun Uranga, Estibaliz Uranga, Roberto Uranga, Rafael Blanco, Sergio Blanco, José Ipiña, Javier Garay and Francisco 'Paco' Panera. Eventually they decided to form a vocal group named Voces y guitarras ('Voices and Guitars') with folk and spiritual music and The Beatles as their influences. During their rehearsals, their brothers and friends joined. They sang in various locations at Bilbao.

In 1967, in the Basque city of Bilbao, three young sisters, Amaya, Izaskun and Estibaliz Uranga, formed a vocal trio named Las Hermanas Uranga (The Uranga Sisters). 6 Songs not included in the original albums.

Amaya uranga young