ABBA was a band of four Swedish singers - Agnetha, Bj枚rn, Benny and Anni-Frid. The name ABBA is just the first letter of each of their names. They became famous in 1974 by winning Eurovision (a giant European song contest) with a song called Waterloo. They sang in English so people all over the world could sing along, and they sold over 380 million records.
Spotify started in Sweden in 2006. Two friends, Daniel Ek and Martin Lorentzon, had a simple idea: what if people could listen to almost any song in the world, instantly, by just searching for it? Today, over 600 million people around the world use Spotify. The whole company is run from Stockholm.
Sweden also makes lots of songs that you have probably heard without realising. A songwriter called Max Martin, from a small Swedish town, has written or co-written more big hit songs than almost anyone else in history. He has written songs for Taylor Swift, Ariana Grande, the Weeknd, Coldplay - the list goes on. He has had over 25 songs reach number one in the US.
Why is Sweden so good at music? Lots of reasons. Music lessons are free for many Swedish children - the country has special music schools called 'kulturskolan' open to every child. Long, dark winters give people lots of time indoors to write songs. And Sweden has a long tradition of choirs - around one in ten Swedes sings in a choir.