Life is fragile.

On a Sunday morning in September 1963, a bomb planted by white terrorists tore open Birmingham’s 16th Street Baptist Church.

Timed to explode just before the 11 a.m. service, it knocked down walls and blew out windows. Four young girls were crushed under the debris.

The deaths of Addie Mae Collins, Cynthia Wesley, Carole Robertson and Denise McNair shattered a community and woke up a nation.

The world saw the insanity of those who fought for segregation, and the depravity of the venal politicians who egged them on. Out of that evil something positive emerged. Historians credit the horror of the killings with propelling the passage of the Civil Rights Act the next year.

This summer, the four girls will be remembered with a memorial as beautiful as the crime was repugnant. As the National Center for Civil and Human Rights opens its doors starting next Monday, visitors will see portraits of the four girls crafted in stained glass.

The four windows will be one of the focal points in the center’s civil rights exhibit, marking a turning point in the exhibit itself, where darkness gathers, just before the light. They were killed less than a month after the triumphant March on Washington.

Priscilla and Tom Malone, stained-glass artists from Portsmouth, R.I., crafted the windows, and found themselves drawn irresistibly into the story.

“I’m going to be so emotional when I see them suspended,” Priscilla said of the portraits earlier this spring.

She said she was looking forward to the time when the public — and the families of the girls — will be invited in. “I don’t know how the families are going to survive this impact, but I’m going to be a wreck,” she said. “I really would love to hug them and embrace them.”

The Malones practice a 1,000-year-old craft using antique glass and European technique, although the tall arched windows are created to suggest the windows of 20th-century Southern Baptist churches.

They worked with a “wish list” of design elements provided by the center’s exhibit designers, including George C. Wolfe and the Rockwell Group.

Priscilla painted watercolor renderings of her proposed design and created a full-size “cartoon” showing how the different elements of the colorful puzzles would be pieced together. Tom cut the glass to fit the cartoon, placing the sections in a framework of channels made out of soft lead, which he soldered and sealed with putty.

Their associate, New York-based artist Indre McGraw, painted the faces of the girls onto sections of tinted antique glass, using pigments that combine ground colored glass with a binder. When the painted glass is fired, the pigment melts into the background glass, and is permanently bonded to it.

“There are multiple firings,” said Priscilla Malone. The faces are detailed, down to the lashes and the highlights shining off their eyes. Surrounding their faces are the hot colors of the explosion, reds and oranges that suggest “Wow, that hurt. That was murder.”

Like the movement, like life itself, the windows are breakable, but tough. They emerge from the flames of the kiln with their colors shining, their beauty enhanced.

Addie Mae, Cynthia and Carole were 14 years old and Denise was 11 when they were killed. The older children would have been near retirement today if they had lived. “They would been 65 right now,” Priscilla said. “Who knows what they would have contributed in life?”