Approximately 5,000 people attended a rock concert at the Palau Sant Jordi arena in Barcelona after passing a same-day screening test for Covid-19.
The crowd gathered to see indie rock band Love of Lesbian, and the show took place with special permission from Spain's health authorities in a pilot to examine whether the rapid testing system could effectively prevent Covid-19 outbreaks.
"Welcome to one of the most exciting concerts of our lives!" said Love of Lesbian lead singer, Santi Balmes.
Fans took a test earlier in the day and did not have to keep physically apart, but they still wore masks.
This is one of the largest gatherings in Europe in more than a year since the pandemic began.
Ticket-holders were only permitted to enter the stadium once a negative result code was sent to their phones, and temperatures and IDs were checked at the door.
Staff from a local hospital and event promoters teamed up to carry out rapid testing in booths within tents at three local venues.
"We expect it to be completely safe. Over the next 14 days we will look at how many of the audience test positive for Covid and will report back," commented doctor Josep Maria Llibre.