LOWER MANHATTAN (PIX11) — Victims’ families, Vice President Kamala Harris, and many more will gather Sunday in Lower Manhattan to mark 21 years since the 9/11 terror attacks.

New Yorkers are already getting a glimpse of one stark reminder of that day with the annual Tribute in Light, a display shining some four miles into the sky above Ground Zero in memory of the nearly 3,000 people lost in the attacks.

Also top of mind are those who have died in the years since of 9/11-related illnesses, as well as the thousands more now battling cancer and other health problems connected to the attack and its aftermath.

The pursuit of justice continues to this day. While U.S. forces killed a top Al-Qaeda leader earlier this summer, the self-proclaimed mastermind of the attacks, Khalid Shaikh Mohammed, is still awaiting trial along with four other men, amid years of legal setbacks.

But on Sunday, tribute will be paid to those the nation and the city has vowed to never forget.

With the passing of Queen Elizabeth II on Thursday, a different tribute was paid, with One World Trade and other city landmarks lit in purple to honor the monarch. A memorial garden named for the sovereign sits a short distance from Ground Zero at Hanover Square. The queen visited the site in 2010 to honor the 67 British victims of the attacks.

Several ceremonies are planned starting Friday and running through the weekend around the tri-state area to preserve the memories of those lost 21 years ago.