The main storyline is set in the Royal Mint of Spain in Madrid, but the exterior scenes were filmed at the Spanish National Research Council (CSIC) headquarters for its passing resemblance to the Mint, and on the roof of the Higher Technical School of Aeronautical Engineers, part of the Technical University of Madrid. The hunting estate where the robbers plan their coup was filmed at the Finca El Gasco farm estate in Torrelodones. Interior filming took place at the former "Locked Up" sets in Colmenar Viejo and at the Spanish national daily newspaper "ABC" in Torrejón de Ardoz for printing press scenes. As the show was designed as a limited series, all sets were destroyed once production of part 2 had finished. Parts 3 and 4 were also filmed back-to-back, with 21 to 23 filming days per episode. Netflix announced the start of filming on 25 October 2018, and filming of part 4 ended in August 2019. In 2018, Netflix had opened their first European production hub in Tres Cantos near Madrid for new and existing Netflix productions; main filming moved there onto a set three times the size of the set used for parts 1 and 2. The main storyline is set in the Bank of Spain in Madrid, but the exterior was filmed at the Ministry of Development complex Nuevos Ministerios. A scene where money is dropped from the sky was filmed at Callao Square. in Carrascal del Río served as the exterior of the Italian monastery where the robbers plan the heist. The motorhome scenes of the Professor and Lisboa were filmed at the deserted Las Salinas beaches in Almería to make the audience feel that the characters are safe from the police although their exact location is undisclosed at first. Underwater scenes inside the vault were filmed at Pinewood Studios in the United Kingdom. The beginning of part 3 was also filmed in Thailand, on the Guna Yala islands in Panama, and in Florence, Italy, which helped to counter the claustrophobic feeling of the first two parts, but was also an expression of the plot's global repercussions. The series' theme song, "My Life Is Going On," was composed by Manel Santisteban, who also served as composer on "Locked Up". Santisteban approached Spanish singer Cecilia Krull to write and perform the lyrics, which are about having confidence in one's abilities and the future. The theme song is played behind a title sequence featuring paper models of major settings from the series.