More than a million people are said to have taken part in a march in Madrid to oppose government plans to liberalise Spain's abortion law.
Several dozen centre-right opposition party joined the demonstration, which was backed by Roman Catholic bishops.
Socialist Prime Minister Jose Luis Rodriguez Zapatero wants to introduce abortion on demand.
At present, a pregnancy can only be terminated in mainly Catholic Spain under specific circumstances.
It is the latest in a series of ethical issues which have pitted the Catholic right against the government, which has legalised gay marriage and made divorce easier.
THE LEFT'S GRAMSCIAN AGENDA IS FAILING.
THE PEOPLE ARE REBELLING AGAINST THE LEFT ALL OVER THE WORLD.
THE LEFT IS THE PARTY OF DEATH: EUTHANASIA; ABORTION; APPEASING JIHAD; AND THE PARTY OF HIGHER TAXES AND REDISTRIBUTIONISM.
MOST PEOPLE EVERYWHERE WANT LIFE, LIBERTY AND THE OPPORTUNITY TO PURSUE THEIR OWN DREAMS.
ONCE SECURED THE PEOPLE ARE LOATHE TO GIVE THEM UP.
WHEN THE PEOPLE WAKE UP - AS THEY ARE WITH THE TEA PARTIES HERE AND THIS ANTI-ABORTION RALLY IN MADRID - THE PEOPLE ARE UNSTOPPABLE.