Where was the 1920 Summer held?
where it was held refers to city_name; the 1920 Summer refers to games_name = '1920 Summer';
SELECT T2.city_name FROM games_city AS T1 INNER JOIN city AS T2 ON T1.city_id = T2.id INNER JOIN games AS T3 ON T1.games_id = T3.id WHERE T3.games_name = '1920 Summer'