As the community in Littleton, Colo., observes the 20th anniversary of the Columbine shooting on April 20 with a day of service and an alumni gathering, some are still frustrated by a lack of progress in preventing similar attacks. “I think a lot of us are looking at it and saying, OK, we’re done talking about that day. We’re done talking about where we were, how we found out. Now let’s talk about what we can do together, what we can do about it,” says Coni Sanders, whose father, Dave Sanders, was among 13 people slain at Columbine. She now works with violent offenders as a forensic therapist, aiming to better understand their behavior and save other people from becoming victims. “And I really feel like we had so many opportunities after Columbine. We thought that would be enough for the world to change, and it didn’t.” In this photograph, flowers adorn the memorial in Littleton on April 18. Read more at the link in bio. Photograph by @theostroomer for TIME

Kiki Leyba remembers April 20, 1999, as a day of two life-altering extremes. He was a first-year Columbine High School teacher meeting with the principal, who had just offered him a contract to continue teaching there—his dream job—when gunshots rang out in another part of the building. What he called "one of the top-10 best mornings of my life” turned into a “horrifically tragic afternoon,” as two students killed 13 people in one of the deadliest school shootings in American history. Leyba, 57, is one of 13 educators still teaching at Columbine 20 years later, working with students who weren’t even born when the shooting took place but who have grown up familiar with the routines of gun violence at a time when mass shootings occur with alarming frequency. Survivors are often called upon for their perspectives, even as many still struggle to make sense of what happened in 1999 and have no simple explanations for why it keeps occurring. “We’ve become the weird grandparents of school shootings, and when they happen, inevitably, people will reach out to us—sometimes it’s media, sometimes it’s communities—to try to understand why is this still happening,” Leyba says. “Why would we know?” In this photograph, Leyba poses for a portrait at a memorial site in Littleton, Colo., on April 18. Read more at the link in bio. Photograph by @theostroomer for TIME

Residents dressed in their own version of Roman soldiers, called Moriones, parade the streets as they observe the week of lent in Boac, south of Manila in the #Philippines, on April 18. Photograph by @jeszmann—@gettyimages

This week, @aclu_nationwide asked New Mexico's governor and attorney general to investigate United Constitutional Patriots, a right-wing militia group operating on the U.S.-Mexico border that reportedly detained about 200 #migrants. The American Civil Liberties Union denounced the militia members' actions in an April 18 letter, saying it has no legal authority to detain or arrest migrants in the United States. "We cannot allow racist and armed vigilantes to kidnap and detain people seeking asylum," the letter states. Speaking to @nytimes, the group's spokesman said “if these people follow our verbal commands, we hold them until Border Patrol comes ... Border Patrol has never asked us to stand down.” In these photographs from March, an American flag rests atop a sleeping bag in a militia camper in Anapra, N.M.; members patrol the border in Sunland Park, west of El Paso; and copies of the Constitution are seen inside a camper. Photographs by @paulratje—@afpphoto/@gettyimages

Arundhati Katju and Menaka Guruswamy, two public-interest litigators who won a landmark rights case in #India, are among the 100 most influential people of 2019. "Arundhati and Menaka have helped take a giant step for LGBTQ+ rights in the world’s largest democracy," writes @priyankachopra. "In their committed fight for justice, they have shown us that we as a society must continue to make progress, even after laws are changed, and that we must make an effort to understand, accept and love." Read more, and see the full #TIME100 list, at the link in bio. Photograph by @paridukovic for TIME

@jairmessiasbolsonaro, the president of #Brazil, is one of the 100 most influential people of 2019. "Fascination with his appetite for controversy obscures an important truth about his country: Brazil remains a dynamic democracy with robust institutions that will limit both the good and the harm he might do," writes @ianbremmer. Read more, and see the full #TIME100 list, at the link in bio. Photograph by @danielmarenco for TIME

@radhyaalmutawakel is one of the 100 most influential people of 2019. "Radhya and her colleagues face risks every day to uncover the human costs of war" in #Yemen, writes @berniesanders. "For leading this work, Radhya Almutawakel deserves recognition as one of the truly courageous among us." Read more, and see the full #TIME100 list, at the link in bio. Photograph by @heathersten for TIME

@iamreginaking is one of the 100 most influential people of 2019. "We’re on the battlegrounds together as women and women of color," writes @violadavis. "We connect as people who see other artists and who really take it upon ourselves to elevate them." Read more, and see the full #TIME100 list, at the link in bio. Photograph by @marcogrob for TIME

@bts.bighitofficial is on TIME's list of the 100 most influential people of 2019. "Behind those three letters are seven astounding young men who believe that music is stronger than the barriers of language," writes @iamhalsey. "It’s a universal dialect." Read more, and see the full #TIME100 list, at the link in bio. Photograph by @nhuxuanhua for TIME

Christine Blasey Ford is one of the 100 most influential people of 2019. “Through her courage," writes @kamalaharris, "she forced the country to reckon with an issue that has too often been ignored and kept in the dark.” Read more, and see the full #TIME100 list, at the link in bio. Photograph by @daniellelevitt for TIME

@taylorswift is one of the 100 most influential people of 2019. "The magic of Taylor Swift doesn’t come from the lights, dancers or fireworks (although all of that is incredible)," writes @shawnmendes, "but from the electrifying connection that she has with the people who are there to see her." See the full #TIME100 list at the link in bio. Photograph by @paridukovic for TIME

Dwayne Johnson (@therock) is one of the 100 most influential people of 2019. "He is the true embodiment of the idea that people may forget what you said, people may forget what you did, but people will never forget how you made them feel," writes @gal_gadot. See the full #TIME100 list at the link in bio, and swipe for a video interview with Johnson. Photograph by @paridukovic for TIME. Video by @fancybethany and @spencerbakalar