|Paralympic Games on the BBC|
|Venue: Rio de Janeiro, Brazil Dates: 7-18 September Time in Rio: BST -4|
|Coverage: Follow on BBC Radio 5 live and via live text commentary|
How does it work?
Goalball is a sport for athletes with visual impairments. It is played by two teams of three using a ball with bells inside. The ball is the size of a basketball but twice the weight.
The game is played on a standard volleyball court and the goals are nine metres in width, which is the same length as the court.
All players on the court must be blindfolded and the aim is to roll or throw the ball into the opponents' goal as many times as possible within two halves of 12 minutes.
The ball must make contact with certain areas of the court and once it has passed these points, defenders will attempt to block the ball with their bodies.
Beyond the group stages, drawn matches are resolved by two extra halves of three minutes. If the game is still tied after this period, extra throws will decide the winner - this is goalball's equivalent of a penalty shootout.
Who are the British medal hopes?
Great Britain did not qualify a men's or women's team for the Rio 2016 Paralympics after failing to reach both the 2014 World Championships and the 2015 European Championships.
Who are the other challengers?
In the men's event, hosts Brazil go into the Rio Paralympics as world champions but they will face strong opposition from rivals Finland, who beat them to Paralympic gold in 2012.
In the women's event, China and Japan have developed an intense rivalry since their Paralympic final in London four years ago with the USA also among the favourites for gold.
Did you know?
There are 11 different referees in a game of goalball. There are two main referees responsible for officiating the match, who use different whistle blows and verbal commands so the players understand.
Four officials are located near the goalposts and they are responsible for replacing balls and guiding substituted players on and off the court. The remaining officials work away from the court on the table recording scoresheets and the remaining time left in the match.
ParalympicsGB London 2012 medals