RICHMOND, Calif. (Reuters) - They welded pipes. They drew blueprints. And, of course, they fastened munitions and machine parts together with rivets.

The Army Engineer Spouses Club welcome a group of more than 30 Michigan-based "Rosie the Riveters" at Ronald Reagan International Airport in Arlington, Virginia, U.S., March 22, 2016. Cynthia Mitchell/U.S. Army Corps of Engineers, Baltimore District/Handout via REUTERS

Now, seven decades after World War Two ended, a surviving handful of the women who marched into factories and shipyards, redefining workplace gender roles to help keep America’s military assembly lines running, were honored on Tuesday in the country’s first official National Rosie the Riveter Day.

Eleven Rosies, all in their 90s, were feted with speeches and a U.S. Senate resolution at the Rosie the Riveter WWII Home Front National Historical Park, which opened in 2000 just north of San Francisco in Richmond, California.

“Without these amazing ladies, we wouldn’t have won the war,” Kelli English, a park interpreter told a news conference on Tuesday.

The women wore red, polka-dotted blouses and were treated to the planting of a rose bush at the park’s museum in their honor.

“Well it’s about time,” honoree Marian Sousa, 91, said in an interview ahead of the ceremony. “It shows that women are not only capable now, but they were capable then.”

Sousa, a resident of El Sobrante, California, worked as a “draftsman” creating blueprints for warships at the Kaiser Shipyard during the 1940s.

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Her sister, Phyllis Gould, 95, and fellow Rosie worker Anna “Mae” Krier, 91, of Levittown, Pennsylvania, led the campaign pushing for a national day of recognition for the last few years.

“This is big,” Gould said in an interview on Monday.

Gould, who worked as a Navy-certified welder at the Kaiser-Richmond shipyards during the war, said it irks her that her slice of history is often overlooked.

Krier flew to Washington for a separate but related event attended by Senator Bob Casey, of Pennsylvania, a chief sponsor of the Rosie resolution, and other members of Congress.

Facing a labor shortage as many able-bodied males joined the U.S. Armed Forces between 1940 and 1945, America’s industrial arsenal turned to women to help fill jobs previously reserved strictly for men to produce ships, planes, munitions and other war supplies.

The share of U.S. jobs occupied by women grew from 27 percent to 37 percent during the war years, with nearly one in four married women working outside the home by 1945, according to the National Park Service.

It is unclear how many Rosies are still living today.

The Senate resolution pays tribute to 16 million women it says worked or volunteered for the U.S. war effort, including many who toiled for the American Red Cross, hospitals, rationing boards and other non-factory settings.

The phenomenon was captured in the iconic “We Can Do It!” posters from the era, picturing a determined-looking woman in blue factory togs, her hair swept back in a red scarf, rolling up a sleeve to show off her biceps.

Marian Wynn, 91, a former welder now living in Fairfield, California, agreed the honor was long overdue.

“I think we deserve it,” she said.