Flower by flower, Kasey Thompson and her young helpers created a huge altar archway of tissue-paper marigolds, a passage through which spirits may enter on the Day of the Dead.

Next came candles, candy, and toys — a small truck, a Barbie doll, a stuffed blue elephant. And finally, photos of the children, lovingly framed.

The altars built for Día de los Muertos traditionally honor family members who have passed on.

But in the heart of South Philadelphia, where immigrant roots run deep, community members have spent weeks creating an ofrenda to honor people they never knew — migrant children who died while trying to cross the Mexican border into the United States. Some died in the arms of their families. Others died in the custody of U.S. immigration authorities, at least six since September 2018, raising questions about the conditions in which they were held.

“In some ways, it’s infuriating that we’re dedicating an altar to young children,” said lead artist Erika Guadalupe Núñez. “But [their souls] still need a place to go. They need to be remembered.”

The Day of the Dead is widely celebrated in Mexico, Central America, and parts of South America. In this country, it’s often confused with Halloween, seen by partiers as a time to drink and dance in skeleton-face makeup.

The true meaning of the holiday is defined by the recognition that death is part of life, and that loved ones never really leave so long as they are remembered.

“On Halloween, we fear,” said Paloma Collazo-Vargas, who organizes the youth program of Juntos, the Latino advocacy organization. “On Day of the Dead, we honor and love.”

All month, neighborhood residents and friends have met at the Washington Avenue offices of Juntos to prepare offerings and ready the altar. When the work was finished on Tuesday night, bright strings of papel picado crossed the room. And the faces of the children stared out:

Nineteen-month-old Mariee Juárez of Guatemala, who died of a viral lung infection a few weeks after her release from a federal detention facility. Felipe Gomez Alonzo, 8, who died in custody of the flu and a bacterial infection after traveling from Guatemala. And a smiling father-daughter portrait of Oscar Alberto Martinez Ramirez and 23-month-old Valeria, who came north from El Salvador and drowned while trying to cross the Rio Grande into Texas.

The father and daughter became widely known in death, after a photo showed them face down in the muddy riverbank near Matamoros, Mexico, the girl’s arm around her father’s neck.

The idea for the altar sprang not just from news of child deaths, but in recognition that the nation’s fiery debate over immigration — particularly around the treatment of children — has reached deep into Pennsylvania.

Today, the Berks family detention center in Leesport holds enough migrant children to open a day-care center. Arizona-based VisionQuest is fighting in court to start a North Philadelphia shelter for 60 boys ages 12 to 17. Behavioral-health provider Devereux wants to house 42 immigrant children ages 5 to 12 in Devon, and Bethany Christian Services plans to open a 12-bed facility in Bensalem.

The agencies say they’ll house “unaccompanied minors” who arrived at the border alone.

Almost 73,000 children were apprehended at the border through August of fiscal 2019, up 60% from the same time in 2018, according to U.S. Customs and Border Protection. Almost all come from Guatemala, Honduras, or El Salvador, where gangs and street violence are endemic.

Family crossings also have soared. During the same time period, the adults and children apprehended as part of a family unit climbed 400%, from about 91,000 to about 456,000.

The journey from Central America to the U.S. is more than a long walk. It’s a dangerous trip that kills hundreds of migrants each year. For children of any age, the mere attempt to leave one country for another poses a “serious risk to life,” according to the International Organization for Migration, a U.N.-related agency.

IOM says 43 children died on the U.S.-Mexico border from 2014 to 2019, though that’s likely an undercount. On a single day in June, Texas authorities reported the deaths of a toddler and two babies.

“I can’t not think about it,” said Alicia Frausto, 24, who sat at a table at Juntos painting colorful faces on small sugar skulls. “There are deaths occurring at the border right now.”

The 1,933-mile border runs through the deserts, mountains, and rivers of four U.S. states, Texas to California. Hugo Castro, a board member at San-Diego-based Border Angels, said he’s not surprised that people in Philadelphia would want to honor children who died on the journey.

“More and more people are getting interested in expressing their worry,” he said.

Every Day of the Dead altar contains similar elements. All welcome returning spirits to rest and eat after their long journey from the hereafter.

The centerpiece tends to be a large photograph of the deceased. Placed nearby are juice, bread, and flowers. Candles provide a lighted route to the world of the living. Belongings of the departed also may be placed on the altar, to help the spirit recognize that he’s home.

At Juntos last week, orange paper trimmings littered the floor, as children and parents crafted huge marigolds, the flower associated with the holiday. Spilled sugar covered tables like soft-fallen snow, the bulk of it mixed and pressed into skeleton-skull molds.

The children who worked with sticky fingers, and the adults who assisted them, wanted to ensure that candy would be on the altar. That way the children beckoned from the afterlife would have something sweet to eat.

“They died very young,” said Carmen Maria, a community member who declined to share her last name as she placed the photos on the altar. “They were just children.”

The altar can be seen at Juntos’ Day of the Dead event, 600 Washington Ave., Unit 18UA, 5 to 8 p.m. Friday.