Find the names of stadiums that the most swimmers have been to.
SELECT t3.name FROM record AS t1 JOIN event AS t2 ON t1.event_id  =  t2.id JOIN stadium AS t3 ON t3.id  =  t2.stadium_id GROUP BY t2.stadium_id ORDER BY count(*) DESC LIMIT 1
SELECT t3.name FROM record AS t1 JOIN event AS t2 ON t1.event_id  =  t2.id JOIN stadium AS t3 ON t3.id  =  t2.stadium_id GROUP BY t2.stadium_id ORDER BY count(*) DESC LIMIT 1
[{'name': 'Gazprom Arena'}]