Handball is played by two teams of seven players. The aim is to throw a ball into a goal at the other end of the court, a bit like football. But you can pick the ball up and throw it. Players run, pass, leap up into the air, and shoot. It is fast - games are full of jumping, sprinting and quick passes.
At the 2008 Beijing Olympics, the Icelandic men's handball team won the silver medal, beating much bigger countries. It was an extraordinary moment. The whole country watched on television. When the players came home, they were greeted at the airport like superheroes.
Iceland's secret weapon is its sports halls. Almost every village - even small ones - has a heated indoor sports hall, because the weather is too cold for many outdoor sports in winter. Children grow up playing handball inside, all year round, often from the age of six.
Football is also hugely popular. Iceland qualified for the 2016 European Championship and the 2018 World Cup - and even drew with England! Icelandic fans are famous for the 'Viking Clap' - a slow, loud HU! that thousands of fans do together, with hands raised over their heads.