A summary of the holidays in Spain
The government in Spain decides which days are national holidays each year, but the number of vacation days is different in each region. Local governments decide when regional holidays are, not national governments.
There are a lot of people in Spain during national holidays. Many employees take a four-day holiday ("puente" in Spanish) if their holiday is on a Thursday or Tuesday. If a holiday falls on the weekend, it might be moved to the next working day instead. But this isn't true for every company.