Information:  - The 1950 LEN European Aquatics Championships were held 20 -- 27 August 1950 in Vienna , Austria .  - Diving is the sport of jumping or falling into water from a platform or springboard, usually while performing acrobatics. Diving is an internationally recognized sport that is part of the Olympic Games. In addition, unstructured and non-competitive diving is a recreational pastime.  - Open water swimming takes place in outdoor bodies of water such as open oceans, lakes, and rivers.  - Water polo is a team water sport. The game consists of four quarters in which the two teams attempt to score goals by throwing the ball into their opponent's goal. The team with the most goals at the end of the game wins the match. A team consists of 6 field players and one goalkeeper in the water at any one time. Except for the goalkeeper, players participate in both offensive and defensive roles. In addition to this, teams may have substitute field players and substitute goalkeepers who are not in the water. Water polo is typically played in an all-deep pool 7 feet deep and players require stamina and endurance to play the game.  - The European Aquatics Championships is the continental Aquatics championship for Europe, which is organized by LENthe governing body for aquatics in Europe. The Championships are currently held every two years (in even years); and since 1999, they have included 4 aquatics disciplines: Swimming (long course/50m pool), Diving, Synchronized swimming and Open water swimming. Prior to 1999, the championships also included Water polo, which beginning in 1999 LEN split-off into a separate championships. The open water events are not held during the Olympic year.    Given the information above, choose from the list below the object entity that exhibits the relation 'sport' with the subject '1950 european aquatics championships'.  Choices: - diving  - sport  - swimming  - synchronized swimming  - water polo
swimming