1. The monument consists of twenty-one hexagonal marble pillars set in a pyramid. The pillars range in height between one and six feet, representing the range in age of the victims. The oldest was seventy-four and had stopped to pick up hamburgers on the way to visit his grandchildren. The youngest was six months old and died in the arms of his mother, also murdered.

2. The plaque in front of the monument reads, “Dedicated as a living memorial to those who died so tragically on July 18, 1984 and to those survivors who continue to bear the scars of that day. Dedicated December 13, 1990.” It sits at the corner of San Ysidro Boulevard and Averil Road in San Diego. “They are bonded together in the hopes that the community, in a tragedy like this, will stick together, like they did,” said the monument’s artist Roberto Valdes, a native of Mexico, the home country of so many of the victims, and a graduate of the college on whose grounds the monument stands.

3. The monument is a memorial to the lives lost in the worst mass murder in the history of California. At the time, the twenty-one victims made the event the worst massacre of its kind in U.S. history. It would be surpassed seven years later by the twenty-three diners killed at a Luby’s Cafeteria in Killeen, Texas, in 1991, the thirty-two students and university staff members killed at Virginia Tech in 2007, the forty-nine dancers and staff members killed at the Pulse nightclub in Orlando in 2016, and the sixty fans of country musician Jason Aldean killed at the Harvest Music Festival in Las Vegas in 2017.

4. The memorial to the twenty-three victims of the Luby’s Cafeteria Massacre is a pink granite stone that lists the names of the victims and the date. It sits a mile and a half north of the crime scene, on the grounds of the Killeen Community Center. The Luby’s Cafeteria remained open for another nine years following the tragedy. Virginia Tech’s memorial is an artist’s rendering of a spontaneous gesture. In the hours following the murders, students placed a ring of thirty-two stones on Drillfield, a twenty-two-acre open space at the center of campus. The permanent memorial would incorporate the idea of a circle of stones into its final design. The Pulse nightclub building remains encircled by a barrier wall covered with photos of the murdered. The city of Orlando has assumed responsibility for a permanent memorial following the 2023 dissolution of the organization tasked with doing so. The memorial to the murdered in Las Vegas, when finished, will consist of an equal number of slender light sculptures emitting beams into the sky and positioned on the site of tragedy. The sculptures will sit in a ring inside a memorial park of 22,000 lights, one for each of the attendees of the concert that evening. The community healing garden, begun in the days immediately following the massacre, sits six miles north.

5. There is no agreed-upon definition by law enforcement of a “mass murder.” The Investigative Assistance for Violent Crimes Act of 2012, signed into law the month after the murders of twenty students and six staff members at Sandy Hook Elementary School—in order to coordinate efforts between federal and local law enforcement—standardized the term “mass killing” as an update to “mass murder.” The new law was not designed to differentiate between “mass killing” and “serial killing” or “terrorism,” even though the FBI investigates each differently. Journalistic accounts of these acts of horror will usually refer to mass killings as those with one or more perpetrators in a contained public location over a continuous stretch of time, a series of similar murders with a “cooling off period” between as “serial killing” and a violence resulting from advanced planning, teams of killers and political motivation as terrorism. The blurred borders of these terms speak to the need to understand and investigate them as different and also their ubiquity.

6. There is no agreed-upon distinction between a memorial and a monument. The U.S. National Park Service considers anything so deemed by an Executive Order “a monument,” regardless of size or what is being commemorated. A best-guess consensus, based on the opinions of historians, geographers and architects, would be that a monument commemorates a special person or event; a memorial does this, too, but always in the context of loss. Our collective feeling around the terms might also contain the stipulation that “monument” implies something larger than its visitors, the main feature of the landscape it inhabits. A memorial is designed for its visitors and feels incomplete without them.

In the United States, public commemoration of loss shifted from monument to memorial after World War II. Since then, we tend to grieve in spaces designed for an equal exchange between the mourner and the physical structures representing the mourned.

7. Our monument is a memorial to an act of mass murder on the site of that mass murder. Except the place it happened no longer exists. The horrific events of that late Wednesday afternoon, in the middle of summer, forty years ago, took place at a McDonald’s, situated between a doughnut shop and a post office, on the southern reaches of a city about two miles from the U.S./Mexico border. The McDonald’s Corporation repaired the restaurant within two days and hoped to reopen it, but following a week’s worth of meetings with the community, reversed this decision.

8. The building was torn down that fall. Before then, the community covered the site with flowers, candles, fruit, and banners. “We share your grief,” reads one. “United in tragedy,” reads another. Running almost the length of the roof, hung from the eave, are the words “BUILD A MEMORIAL PARK” in block letters.

The practice of transforming sites of death into living memorials, altars for the living to help the dead move from this world to the world of spirit, dates back to the indigenous communities of pre-Columbian Mexico.

McDonald’s would donate the land to San Diego, which in 1988 sold it to Southwestern College, with the agreement that three hundred square feet of the site be dedicated to a permanent memorial.  The memorial now sits at the foot of the Southwestern College Higher Education Extension Building, surrounded by a knee-high fence. Before, the community maintained a wooden shrine designed by local teacher Tom Arena and his wife Alicia, on the vacant lot at 460 West San Ysidro Boulevard. It stood for nearly five years, despite vandalism and threats to remove it.

The donation came with the condition that no other restaurant could be built on the site. Within a year, McDonald’s opened another location a few blocks away.

9. Immediately following the memorial’s dedication, the flat tops of its pillars were used as altars, much as the Arenas’ altar and the McDonald’s had been. Southwestern College has since placed the memorial behind a fence. To this day, flowers, candles, and photographs are laid at the memorial every July 18.

10. As Kenneth E. Foote explains in his book Shadowed Ground: America’s Landscapes of Violence and Tragedy, the site—and San Ysidro’s response to it—are considered a turning point in the public commemoration of victims of violence. Before, American communities would often obliterate or repurpose sites where horrible things happened. Shame, wrote Foote, motivated a civic form of forgetting.

This San Ysidro memorial is a site of remembering, independent of the removal of the site of the horror. It extended permission forward in time, for Killeen to memorialize the Luby’s victims without having to excise the restaurant like a tumor, for Columbine High School to build Hope Columbine Memorial Library on school grounds, for Virginia Tech to honor its murdered community members without having to demolish the buildings where they died.

11. “The Worst Day of My Life Is Now New York’s Hottest Tourist Attraction,” read the headline of a 2014 BuzzFeed article by Steve Kandell, whose sister Shari arrived early for work on the morning of September 11, 2001. Mr. Kandell got a VIP tour of the $350 million 9/11 Memorial Museum one week before its opening. “This tchotchke store—this building, this experience—is nothing more than the logical endpoint for our most reliably commodifiable national tragedy,” he wrote of the memorial’s gift shop.

The most resonant word expressing Kandell’s disgust could be “commodifiable” or “tragedy”—but also “national.” A few horrors loom so large they cease to belong to the dead or their loved ones, or even the communities they belonged to—they now belong to history. And history on that scale, for better and for worse, belongs to the public and must give the public what it has come to expect from a field trip.

12. Even for a memorial on a municipal rather than national scale, the different people seated at the table—victims’ families, community leaders, designers, funders, government—will have incompatible needs that feel immovable to each of them. That’s because sitting at that table is an attempt to materialize something that has been stolen and will never be returned.

13. It is disgusting to view memorials in terms of money and real estate, because soon you find yourself making comparisons between the cost of the 9/11 memorials in Shanksville, Pennsylvania, $58 million for the forty passengers on board United Flight 93 versus $350 million for 2,753 victims of the attack on the World Trade Center. Then you think about how often memorial projects drag on for years because there is no easy answer to where the money will come from and who will administer it once it is found. The forty-nine murdered at the Pulse nightclub have no permanent memorial for this reason. For the twenty-one murdered in San Ysidro, family and community members raised the $50,000 for the cost of their memorial.

14. I learned of the San Ysidro McDonald’s massacre in a July 30, 1984, issue of Newsweek. I was obsessed by the 1984 Summer Olympics in Los Angeles and collected any magazine I could find with coverage of the Olympics on the cover. “America’s Best,” read the Newsweek cover. “Is L.A. Ready for the Games?” News of the massacre, 137 miles to the south of Olympic Coliseum, was reported on page 30.

15. Newsweek’s coverage of the massacre featured a photo of Omarr Hernandez, an eleven-year-old boy shot and killed as he approached the McDonald’s on his bicycle with two friends, David Flores and Joshua Coleman. After visiting the doughnut shop next door, the three friends were headed to McDonald’s for ice cream sundaes that the restaurant gave away free on Wednesdays. Joshua Coleman played dead for an hour; he is now an iron worker and father of three. David Flores was killed instantly.

That same summer, I had been given permission to ride my bike downtown in honor of my 11th birthday. My first ride was to a McDonald’s.

16. The moment of silence came to America in the early 20th century and was first used in public to honor victims of the Titanic. The moment of silence does three things: reminds us of the absence created by death, separates remembrance from the noise of everyday life, and creates an aura of holiness not specific to any one faith.

Moments of silence in mourning the victims of mass murder also stand in contrast to the sounds of violence—gunfire, panic, howls of pain. Since mass murders often occur in public places, the cacophony also represents the intrusion of barbarousness on the everyday music of public life.

The survivors of the San Ysidro massacre included several employees of the McDonald’s who spoke of how the violence sounded as though the very space of their job registered the madness of what was happening, the kitchen machines beeping incessantly because french fries were ready but no one could retrieve them, the pinging of Uzi fire off the metal service counter.

17. Memorials are a physical attempt to bring silence to public space. They are always in conflict with the number of visitors they receive and the public spaces where they sit.

18. The killer had driven only two hundred yards from his family’s apartment on Averil Road to the McDonald’s. He visited the San Diego Zoo earlier in the day and had eaten lunch at a McDonald’s across town with his family. When he left the apartment late that afternoon, he told his wife that he was “going hunting for humans.” When asked why she did not call the police, she said her husband “had been saying wild things for a long time.”

19. Guillermo Flores, David Flores’s brother, is a math teacher, a deep believer in the power of education, and an optimist. He often speaks at the annual remembrances and reminds those present to appreciate what we all have, here, now, with the memorial behind him, each pillar laid with flowers and a photo of the murdered.

Gloria Salas, the community activist who lobbied successfully for the memorial, is a quiet presence every July 18th at the site that she helped make possible. She knows the survivors and families of the victims and has made her exasperation public at how easily they seem to slip from memory. “Even kids who come to the college don’t know about it.”

20. The horror of the San Ysidro massacre led to a nationwide buildup of tactical teams embedded in local police departments, trained and armed to respond to mass shootings in public places. The response of the San Diego Police Department that afternoon has been criticized for being slow and unprepared—unprepared since they had only standard issue firearms against a perpetrator with an Uzi, and slow for reasons that remain in question to this day: Can the speed of the response be explained by coincidence, preparedness, or a lack of value placed on the lives of the lost?

There is no clear answer to that. Collectively, our answer in America since has been the omnipresence in local police departments of what San Diego Police Captain Michael Rosario called “special forces specialists”—a military response to violence at our schools, restaurants, offices, and places of entertainment.

21. Both memorials and monuments are physical attempts to suspend time so that the dead are remembered regardless of how long ago we lost them. The permanence of their materials—stone, metal, earth—are chosen to withstand rain and wind but also the fragility of our memory and the assault of information and compounding tragedies hurling us into the future.

Unlike monuments, memorials are an attempt to fill a space that cannot be, to help us remember what can never be the same. We know they are necessary and never enough. Necessary because we forget, never enough because we try to remember.

Kevin Smokler is the author of four books, including Brat Pack America: A Love Letter to ’80s Teen Movies, and the director of the documentary film Vinyl Nation. He lives in San Francisco.