sentences:  Nicknamed "the happy slam" and often referred to as the "Grand Slam of Asia/Pacific" the tournament is the highest attended Grand Slam event, with more than 812,000 people attending the 2020 tournament.It was also the first Grand Slam tournament to feature indoor play during wet weather or extreme heat with its three primary courts, Rod Laver Arena, Melbourne Arena and the refurbished Margaret Court Arena equipped with retractable roofs.The Australian Open is managed by Tennis Australia, formerly the Lawn Tennis Association of Australia (LTAA), and was first played at the Warehouseman's Cricket Ground in Melbourne in November 1905.