In 1980, due to political sanctions resulting from the Soviet invasion of Afghanistan, there was no IMO. Many other international events, such as the Olympic Games, were also cancelled. However, a number of smaller replacement IMOs were held. These included the Austria-Poland Olympiad (which occurred annually anyway, having been established two years earlier), and the replacement olympiads in Mersch, Luxembourg; and Mariehamn, Finland. The olympiad at Mersch was attended by Belgium, Great Britain, the Netherlands, and Yugoslavia; in addition, France sent a team of four observers. The olympiad at Mariehamn was attended by Great Britain, Hungary, and Sweden.