For reference, the HUGE fireworks display always starts shortly before midnight on the 24th July, going into the 25th. The fireworks are shot off in Plaza Quintana, immediately behind the Cathedral. The police stop people entering the Plaza de Obradoiro earlier in the day, as the maximum capacity is reached fairly quickly. Streets surrounding the plaza are usually blocked off, and you will have to walk around the plaza.
If you do not know your way around Santiago, get a free map at the Tourist Information located at #62 Rua do Vilar. (I think I got the number right), just before Plaza Toural.
If you want to view the fireworks, my advice is to go into Alemeda Park. There is a walking path that provides the best viewed of old Santiago and of the Cathedral. Also, there is always huge carnival in the park, so there will be lots of other folks around. MIND YOUR VALUABLES!
Others have already told you about the need for IRONCLAD reservations. There is literally no room at the inn if you show up in Santiago with no reservation. Every year, we direct arriving pilgrims to the bus to take them some four km, backward on the
Camino Frances, the large municipal albergue at Monte de Goia.
Also, throughout the day on the 24th and 25th, there will be a variety of cannon salutes for the Saint and for visiting dignitaries, such as a the King. The Spanish military fire blank ceremonial rounds from several howitzers on a football (soccer) pitch about a kilometer from the Cathedral.
My European friends sometimes get very anxious when they hear the artillery fire. I look at my watch and reassure them that it is the cannons tolling the hour instead of the Cathedral bells, or a salute for the King, Sanitago, or someone else. If you have visited London or Washington for a big event, you will understand what I mean,
I hope this helps.
(which will have splendid view!) would be also one of the albergues in the entrance of Santiago, like Fin del Camino.
