What are the names of stadiums that some Australian swimmers have been to?
SELECT t4.name FROM swimmer AS t1 JOIN record AS t2 ON t1.id   =   t2.swimmer_id JOIN event AS t3 ON t2.event_id   =   t3.id JOIN stadium AS t4 ON t4.id   =   t3.stadium_id WHERE t1.nationality   =   'Australia'
Australian swimmers refers to swimmers with nationality = 'Australia'; names of stadiums refers to selecting the name column from the stadium table;