The Great Barrier Reef Masters Games comprises many sports including swimming.     They were first held in Cairns, Queensland in 2013, and has since been held every second year. The fifth instalment is to be held from 20 to 23 May 2021.      Cairns is the ideal location to host the Games, being one of Australia's most popular holiday destinations with a myriad of local attractions, dining, adventure sports, reef activities and entertainment within close proximity to the city…