May I ask why the most important international art exhibition is held once every two years? For example, how did the Venice Biennale decide to be held once every two years?

The reason why the internationally important art exhibition was set up every two years was to ensure that the items had enough time to be displayed and appreciated by the people. Since the value and appeal of art works usually increase over time, the biannual exhibition allows the items to attract more audiences and collectors during the exhibition period to maintain their appeal and value. In addition, the biannual exhibition could also ensure that different artists and works could be displayed at different times and attract the interest of the audience, thus increasing the variety and richness of the exhibition. The initial establishment of the biannual international art exhibition system may have originated in the 19th century, when some European art institutions and exhibition organizers began to organize regular shows to ensure that the items had enough time and opportunity to be displayed and appreciated. As time went by, the regular exhibition system gradually evolved into a biannual exhibition mode, becoming one of the basic forms of modern art exhibition.