Police and protestors clashed in numerous cities around Spain as people used today's general strike to demonstrate against the government's recent labour reform bill.
Police used tear gas, fired rubber bullets at the ground and made baton charges as strikers in Barcelona smashed windows and set rubbish bins alight. Unions said 800,000 people joined the protest in Spain's second-largest city. Police put the number at 80,000.
Most of the protests were peaceful, but some protesters hurled rocks at bank offices and shop fronts. A branch of the coffee chain Starbucks was set on fire.
In Madrid, 900,000 people took part in protest marches, according to unions. The government did not provide any figures.
Scuffles with police broke out early on Thursday as workers from Spain's biggest unions - the CCOO and the UGT - picketed Madrid's bus depot.
Unions claimed strong support (as high as 80%) at car factories and other industrial sites but the government played down the impact and claimed many services were running as normal.
Land and sea travel were both affected, and domestic and European flights cut to a fraction of normal levels.
The strike is the first major challenge the government has faced since Mariano Rajoy's centre-right party took office after elections last November. Rajoy will unveil measures on Friday aimed at saving tens of billions of euros and making it easier for businesses to sack employees. It hopes the changes will create a more flexible system for businesses and in turn cut unemployment, which is currently the highest in the EU at 23%, but unions claim the labour reform bill will wipe out rights that people fought long and hard for in the past.