It happened late at night, and the early pictures released from the Pulse nightclub in Orlando were confusing, because they showed young men in their best party clothes leaning on each other in a way that could have been friends wandering home after a bartender’s last call, but was instead people running for their lives.

It happened, the shooter’s father told a news station, because his son was angered by seeing two men kissing. It happened, the shooter told a 911 operator, because he had pledged himself to the Islamic State, so he then went and slaughtered 50 people and injured 53 more. An amalgamation of terrorism and hate that found its outlet in a gay club, but could have anywhere.

It happened nearly a year to the day that the U.S. Supreme Court made same-sex marriage legal. In polls, Americans are increasingly accepting of homosexuality — but then, this.

At D.C. Pride on Sunday, the LGBTQ community expresses sorrow and stands in support with the victims of the deadly mass shooting that took place at a gay nightclub in Orlando, Florida. (Zoeann Murphy/The Washington Post)

“I’m struggling to find the words,” says Jim Obergefell, the Ohio plaintiff whose name became the symbol for gay rights when the validity of his own marriage was upheld by the highest court in the land. “To know that a mass shooting — to know it happened in a place where we as a community go to feel comfortable and be ourselves? I knew there would be a backlash against the strides we’ve made. There’s so much hatred directed toward our community, from candidates, from religious fanatics. I’m not surprised something horrible has happened, but I’m surprised at how horrible it is.”

For several years, June has been known nationally as LGBT Pride Month, with dozens of cities hosting parades and festivals to celebrate gay and lesbian heritage. The designation was hard-fought. The Orlando shootings came 2½ years after a Seattle man tried to burn down a gay club with 750 people inside; and nearly 16 years after a Roanoke, Va., man went into a gay bar with a gun and opened fire; and 43 years — on June 24 — after 32 people were burned to death at New Orleans’s UpStairs lounge.

It was a Pride Weekend at the time of the New Orleans attack, too. Several of the identified bodies were never claimed, according to news accounts, because families were too ashamed that their relatives had been found in a place for gay men.

Three miles from Pulse in Orlando, people spent Sunday morning streaming into the Center, an LGBT nonprofit organization and gathering spot. They brought cookies, sandwiches and potato chips, and sat together and cried.

Jeffery Greamo, left, and Jon Paul join in a moment of silence for the victims of the mass shooting during a Pride Month block party in Boston on June 12. (Brian Snyder/Reuters)

One thousand, seven hundred and thirty miles from Orlando, the Albuquerque Pride festival, which had commenced the day before, announced via Facebook that they would be holding a moment of silence, at 2:02 p.m., twelve hours after the shootings began. So would the Boston Pride Festival, its organizers announced. In Detroit, volunteers at Motor City Pride put up a banner: “Our hearts are with Orlando.” In Washington, D.C., organizers of the Capital Pride Festival prepared a statement of solidarity to be read from that festival’s main stage before the day’s events launched, before a planned performance by a gay men’s chorus.

Two thousand, eight hundred and ninety-one miles from Orlando, placards and flowers had gathered in memorials in San Francisco’s Castro neighborhood. “I remember [anti-gay violence] going back to the 1970s,” said Mikel Rosen, a local fashion consultant walking through the neighborhood. “It will never go away. Minority groups will always get persecuted.”

“If you talk to people here, they would say this is lesbian-and-gay specific,” said Mark O’Dudum, an airline technician in San Francisco. “It’s not gay specific. ISIS is a terrorist group.”

The Islamic State has proven that you don’t have to be gay to offend them, you just have to be not-Islamic State. You just have to be a Parisian going to see a concert, or a Belgian trying to get to the airport, or an Iraqi trying to go to a soccer game.

This weekend’s attack was not only the most devastating attack in the history of the LGBT community. It was the largest mass shooting in the history of America.

The blood banks needed blood: O positive, O negative, AB plasma. People rushed to donate. For the day, at least, one Orlando blood bank lifted the ban on gay male donors. Blood was needed, and a catastrophe of unimaginable horror sometimes causes people to evaluate the divisions that have been arbitrarily placed between human beings.

“This morning I spoke with my good friend, Orlando Mayor Buddy Dyer,” said President Obama in a news conference held at the White House. “I conveyed the condolences of the entire American people. This could have been any one of our communities.”

Back at the Center in Orlando, the table full of donated food grew, and so did the crowd. And then, in the middle of an afternoon that had turned sunny and hot, a volunteer came outside to tell mourners who had clustered there that it would be better if they didn’t stand in front of the Center. There had been rumors of drive-by shootings. “Stay inside or go somewhere else,” the volunteer suggested. It still wasn’t safe. Nobody knew where would be safe.

A gunman opened fire on a crowded nightclub in Orlando early Sunday, June 12. He killed at least 50 people. The final death toll is not known, but this shooting is already the deadliest mass shooting in the history of the United States. (Monica Akhtar/The Washington Post)

The mourners obeyed her. And in a nearby hospital, relatives waited for news of their loved ones. And over in Key West, local Pride organizers encouraged people to wear black armbands in solidarity with Orlando. And in Los Angeles, attendees of the local Pride Parade told reporters they would now view it as a march to honor the shooting victims. And in Washington, at the Capital Pride Festival, the 300 singers of the Gay Men’s Chorus of Washington, D.C. took the stage and in one voice started to sing the National Anthem.

Jared Leone in Orlando and Zara Stone in San Francisco contributed to this report.