For details of Siena a world heritage site : https://www.unesco.it/it/PatrimonioMondiale/Detail/109

For details of the Palio di Siena
https://artsandculture.google.com/partner/consorzio-per-la-tutela-del-palio-di-siena

For details of Siena cathedral
https://www.discovertuscany.com/siena/siena-churches/duomo.html