In October, Zaragoza celebrates the Pilar Fiesta.
These are the main annual fiestas in the regional capital of Aragon, characterised by a broad range of activities that fill the streets with fun, colour and entertainment for a week at the least. The programme brings together theatre performances, concerts, children's entertainment (puppet shows, clowns, magic...), shows, dance, bullfights, craft exhibitions, all kinds of music (from regional folk to pop-rock and electronic sounds at the Independent Music Festival) and many more events. There are also fireworks, the traditional "Giants and Big-heads" parade, sports competitions and exhibitions. The "peñas" (fiesta associations) also play a vital role at the celebrations, which get underway with an opening speech at the Town Hall.
The most important day is 12 October, the feast of La Virgen del Pilar, patron saint of the city. A mass Floral Offering takes place from early that morning: thousands of people from all over the world, dressed in traditional costumes, come to Plaza del Pilar Square to leave flowers before the Virgin. Meanwhile, 13 October sees the Offering of Fruit. And at dusk, the Rosario de Cristal takes place. It is a procession of carriages and glass lanterns that runs through the streets of Zaragoza.
If you decide to come, you can book your accommodation in La Posada del Comendador Hostel or Baltasar Gracián Hostel
Source: www.spain.info/en/que-quieres/agenda/fiestas/zaragoza/fiestas_del_pilar.html