The Ministry of Time's HQ are on the abandoned Palace of Sueca, Duque de Alba Square, Madrid.
When the second season went to a hiatus, many fans feared the series was on the verge of cancellation. The hiatus was actually requested by show-runner Javier Olivares who had envisioned the season as two clearly separated halves, with a special a la UK series like Doctor Who (2005) or Downton Abbey (2010) linking both halves. The network refused to produce the special, but granted the hiatus. They just neglected to tell the audience, so Olivares himself had to set the record straight and clear fans fears in interviews.
According to series creator Javier Olivares, their main influences were the novel "The Gates of Anubis" by Tim Powers and the film Time After Time (1979), a personal favorite of his.
Rodolfo Sancho missed several episodes on season 2 because he was shooting Mar de plástico (2015).
To account for Julián's absence, an online audio-diary was created as part on a multimedia experience in which Julián would record weekly entries and the audience would know what he was doing during his time off.
The doorman of the ministry is a big fan of Atlético de Madrid football club. This is an homage to co-creator Pablo Olivares, who died while making the first season.
Two expanded universe stories bridge the gap between seasons 2 and 3. A graphic novel, and a 4-episode audio drama. Both Jaime Blanch (Salvador) and Hugo Silva (Pacino) reprise their roles in the audio series.
Javier Olivares wrote an unproduced movie script about "The Last of the Philippines" in 1998. These soldiers appear as characters in the second season.
Javier Olivares wanted the second season to be split in two, with a longer special in between. That special was never produced, but it very likely turned into the two-parter "Tiempo de Valientes".
Actor Miguel Rellan mentions (episode 2x03)the movie El crack as one of his favourite. He has a role on that movie.