Jazzaldia Activity · Donostia/San Sebastián, Donostialdea, Gipuzkoa San Sebastián Jazz Festival, the oldest in Spain, founded in 1966; its first edition was held on September 10 and 11 of that year, and since 1967 it has been held every third week of July. 1966 Photo: Vidartereyes (CC BY-SA 4.0) What to see and do in Donostia/San Sebastián