More than 1,000 local choirs in towns and cities across the world sang out in unison on Sunday to call for peace in Ukraine.
The event, run by Spanish organisation Choirs for Peace, saw groups in countries including Spain, Portugal, Britain, Italy and Mexico livestreamed on YouTube as they sang together.
In Madrid, hundreds of people gathered outside the Reina Sofia museum. Some held signs saying "peace" and others wore ribbons in the yellow and blue of the Ukrainian flag.
"We want to sing a very simple song called Dona Nobis Pacem, which means give us peace, to ask for peace in Ukraine and in all the other forgotten wars," Mariano Garcia, coordinator for Choirs for Peace, told Reuters.
"Choirs have a social function... not only musically but also emotionally. Music is able to make people connect much more," he said.
The crowd in Madrid was made up of Spaniards as well as other nationalities, including Ukrainians.
"It is very touching, I've been used to singing for many years but it's exciting, it creates a special energy that hopefully helps these people who are suffering so much at this time," said Maite Martin, an administrative assistant who joined the singalong in the Spanish capital.
(Reporting by Elena Rodriguez and Michael Gore; Writing by Jessica Jones; Editing by Pravin Char)