Thousands of anti-abortion demonstrators are marching through Washington to the steps of the U.S. Supreme Court to protest a landmark decision that legalized abortion.

Crowds held signs and chanted while gathering on the National Mall and surrounding streets for the March for Life.

The demonstration this year coincides with the 40th anniversary of Roe v. Wade, the Supreme Court decision that created a constitutional right to abortion. Earlier this week, opponents marked the anniversary with workshops, prayers and calls for more limits on abortion rights.

Among the speakers was former Republican presidential candidate Rick Santorum, who said the country responded with love to the struggles of his daughter, Bella, who was born with a serious genetic condition. He said the family is better off for having Bella in their lives.