It is well known Wales' national anthem is a stirring and thrilling song - one of which has been sung at sports events and stadiums for more than a hundred years.
The anthem, Hen Wlad Fy Nhadau, which translates to Old Land of My Fathers, rang out around the Ahmed Bin Ali Stadium as Wales made history starting their World Cup tournament campaign on Monday night.
As the side stepped out with millions watching around the world, thousands of Welsh fans in the ground sang along with them.
It was the first time it's ever been sung on football's biggest stage. The last time Wales were at a World Cup in 1958, they sang 'God Save the Queen'.
The anthem, and the way it was sung, has been widely praised on social media, including from USA fans.
Singer-songwriter Billy Bragg said, "Well Wales have won the national anthem singing contest. Their players looked proud to belt out their anthem while the US team looked faintly embarrassed to be singing in public".
Another said, "The way Welsh people sing the national anthem is unrivalled".
Broadcaster Dan Walker described it as "pure emotion".
Another said, "Wales national anthem is absolutely elite though tbh."
Wales' debut match ended in a 1-1 draw with the USA after a tense first and second half.
A penalty in the 81st minute from Gareth Bale saw the side equalise in their first World Cup game in 64 years.
Captain Gareth Bale said they had a "good talk from the gaffer" after a disappointing first half, and praised the USA for their efforts.
"We go again", he said.
Manager Rob Page said it was "worth the wait" and thanked the fans, known as The Red Wall, for their support.
Wales' next group game is against Iran on Friday.