Pro-lifers from around the country are gathering in Washington, D.C., Friday for the annual March for Life.
    
This week marks the 40th anniversary of the 1973 U.S. Supreme Court ruling that invented a nationwide right to abortion.
    
"This is a time to think about the 55 million Americans who have died in the last four decades as a result of legal abortion in the United States, so it's a somber moment," Jeanne Monahan, president of the March for Life Education and Defense Fund, told NBC Washington.
    
Tens of thousands of abortion opponents are expected for Friday's noon rally on the National Mall.

"Our hotel block sold out a month in advance of what it's ever sold out, and we've had more media requests than ever before, so we expect really record-breaking crowds," Monahan said.