Memorial events are being held this saturday across the United States in honour of victims of the September 11 terror attacks on its territory 20 years ago.

According to White House, President Joe Biden and first lady Jill Biden plan to visit all three sites where the attacks unfolded: The World Trade Center in New York City, the Pentagon outside Washington, D.C., and the field near Shanksville, Pennsylvania, where United Airlines Flight 93 crashed.

Vice President Kamala Harris will travel to Shanksville with second gentleman Doug Emhoff before they join the Bidens at the Pentagon.

The 20th anniversary comes amid the backdrop of the United States’ chaotic withdrawal from its war in Afghanistan, which was started in response to the attacks.

Biden last week also directed the declassification of certain documents related to the attacks, which the families of some victims have sought in hopes of implicating the Saudi government.

Nearly 3,000 people were killed in the attacks when 19 al-Qaida attackers hijacked four commercial airplanes in a plot orchestrated by Osama bin Laden.

Two planes, American Airlines Flight 11 and United Airlines Flight 175, crashed into the north and south towers of the World Trade Center before American Airlines Flight 77 crashed into the Pentagon.

The passengers of United Airlines Flight 93 fought back against the hijackers before the plane crashed into the filed, missing its intended target in Washington.

The anniversary marks a transitional moment as awareness of the attacks moves from memory to history, said Alice Greenwald, president and CEO of the National September 11 Memorial and Museum.

“The 20th anniversary, in my view, … is the first of the next generation of remembrances,” said Dan Murphy, who is on the team designing the planned visitor education center at the Pentagon’s 9/11 memorial site.

“There’s been 19 times we’ve read the names, we’ve talked about that moment, we’ve somberly looked back. That will never, ever go away. But … on the 20th anniversary, I think this is the first time we talk about 9/11 into the future.”

On Wednesday, the US federal review process concluded and effectively paving the way for Obama Presidential Center that had stalled for four years.

“Today, after a comprehensive federal regulatory review process, I’m proud to announce the Obama Presidential Center will break ground in 2021,” Former US President Barak Obama said on Wednesday.

“Michelle and I couldn’t be more excited to bring this new center of energy, connection, and growth to the South Side of Chicago. Along with the thousands of jobs it will create, our hope is that the Obama Presidential Center can serve as a catalyst for long-overdue investment in and around historic Jackson Park. That’s why we’re working with local partners to create a new destination to help inspire visitors from hope to action, breathe new life into the park, and deliver real benefits to the community we love,” Obama added.

He explained that getting to this point would not have been possible without the many Chicagoans who have been a part of this process. “So I want to thank each and every person out there who helped us reach this milestone—and for their continued partnership in the years to come.”

Federal agencies closed the final review into the project after determining the Obama center’s construction and nearby roadway fixes would not pose a “significant impact” on the environment, according to city and Obama Foundation officials.

With other federal reviews looking into factors such as the project’s effects on historic properties also recently ending, that means preliminary work can start in April and groundbreaking can likely begin as early as August. The Obama Foundation estimates construction will take about four years.

In 2016, Obama announced that Jackson Park, sandwiched between Lake Michigan and Woodlawn, would be the destination of his future presidential center, at the time scheduled to open in 2021.

His choice was heralded by supporters who hoped the project would help revitalize neighboring communities and become a source of pride for South Side locals and visitors alike.

The groundbreaking of the $500 million campus will include a museum, Obama Foundation offices, a public library branch, an athletic center and an outdoor recreation space.

Its opening initially had been set for this year, but four years of obstacles have stood in the project’s way, at times leaving supporters with dashed hopes as groundbreaking repeatedly was delayed.

Maria Elena Hernandez recently retrieved a flowery box tucked in her closet and dusted it off. For more than a decade, she has used it to store tax returns, lease agreements and other documents that she has collected to prove her family’s long years of residence in the United States.

“We have been waiting for the day when we can apply for legal status. In this box is, hopefully, all the evidence we’ll need,” said Ms. Hernandez, 55, an undocumented immigrant from Mexico who arrived in this country with three small children in 2000.

She had just learned of President Biden’s plan to offer a pathway to U.S. citizenship for nearly 11 million undocumented people, announced as part of a sweeping proposal to overhaul the nation’s immigration system.

The bill would allow undocumented immigrants who were in the United States before Jan. 1 to apply for temporary legal status after passing background checks and paying taxes. As newly minted “lawful prospective immigrants,” they would be authorized to work, join the military and travel without fear of deportation. After five years, they could apply for green cards.

The president’s proposal would be perhaps the most ambitious immigration redesign passed since 1986, when President Ronald Reagan signed the Immigration Reform and Control Act, which legalized three million people.

Converting more than three times that many people into full citizens could open the door to one of the most significant demographic shifts in modern U.S. history, lifting millions out of the shadows and potentially into higher-paying jobs, providing them with welfare benefits, health coverage and Social Security eligibility while eventually creating many new voters.

“This is the boldest immigration agenda any administration has put forward in generations,” said Muzaffar Chishti, senior fellow at the Migration Policy Institute. “But given that the Democrats have razor-thin majorities in Congress, the administration needs to have its expectations tempered.” Legalizing just one group at first — say, farmworkers — might be “more realistic,” he said.

In a sign of the hurdles ahead, another one of Mr. Biden’s early immigration initiatives, a 100-day freeze on deportations, was temporarily blocked by a federal judge on Tuesday after a lawsuit by the Texas attorney general, an advocate of the Trump administration’s immigration crackdown.

Immigration reform has stalled in Congress time and again, primarily over what is widely known as amnesty. Despite beefed-up border enforcement and employer sanctions, Mr. Reagan’s overhaul failed to curb the arrival of unauthorized immigrants.

While Congress has wrestled with how to revamp the immigration system, the immigrants have continued to live, work and raise families in the United States. More than 60 percent have resided in the country for more than a decade and they have more than four million U.S.-born children. They account for 5 percent of the work force, representing the backbone of the agriculture, construction and hospitality sectors.

Many came for economic reasons. Others were fleeing political upheaval and violence. And about four in 10 did not enter the United States through the southwestern border. Rather they are visa overstays — tourists, students or temporary skilled workers who never left.

The family of Denise Panaligan, 27, came to the United States from the Philippines in 2002 after her father, a financial analyst, obtained an H-1B visa. They remained after their temporary legal status ran out.

“When people look at us, they don’t think undocumented because we are Asians,” said Ms. Panaligan, a middle school teacher in Los Angeles. “Coming in contact with deportation officers and ICE, we never experienced that. We’re invisible to enforcement.”

But their decision led to other indignities, she said. Her mother had to work as a housekeeper despite having a college education. Denise’s father, Art, died two years ago of brain cancer without ever returning to his homeland to see his own parents because he would not have been allowed back into the United States.

“The Biden plan would fulfill our hope of keeping the family together,” said Ms. Panaligan, who has two younger sisters, one of them born in the United States.

The largest share of unauthorized immigrants is from Mexico. Having survived treacherous river and desert crossings to reach the United States, they found a nation willing to look past laws that prohibit hiring them, to employ them in fields and factories, and in homes as nannies and housekeepers.

Maribel Ramirez and Eusebio Gomez of Mexico have toiled in California’s vineyards since crossing the border 19 years ago. They have managed to buy a home and raise two American-born sons. Their oldest, Eusebio Jr., 17, plans to enlist in the Marines. But Ms. Ramirez said she asked herself, “Why should my son give his life to a country that doesn’t value his parents?”