Four million people have been to the 9/11 Tribute center since it opened 10 years ago. Now, it's moving to a larger home, not just to accommodate more visitors, but also a bigger mission. NY1's Amanda Farinacci filed the following report.

It's one of the most popular destinations in Lower Manhattan. Nearly a half million people a year descend on the 9/11 Tribute Center on Liberty Street. That's a lot of people in just 4,000 square feet of space.

"I would say we've outgrown it," said Wendy Aibel-Weiss of the 9/11 Tribute Center.

While the 9/11 Museum tells the story of the attacks with artifacts, the Tribute Center recalls that day and the aftermath in more human terms. Survivors, rescue and recovery workers, volunteers and family members are on site every day giving their accounts of what happened. Sharing their stories is meant to help them heal.

Their testimonies, plus interactive exhibits and tours, focus not just on the devastation, but also on the resiliency and recovery.

But with 35,000 square feet, the center is expanding its mission.

"Not change. I want to say evolve, to really highlight the recovery of those who are volunteers and share their story, and also highlight the tremendous service that grew out of September 11," said Jennifer Adams of the 9/11 Tribute Center.

An old DMV office down the block at Rector and Greenwich streets will house the new center next spring. It will be divided into three parts, detailing the history of 9/11, the response and recovery, and the volunteerism that grew out of the attacks.

"They will be presented with the horror of that day, but then we will gradually bring them through the space towards what we call seeds of service. What can you do? How can you make the world a better place?" said architect Lee Skolnick.

The new tribute center will come with a renewed focus on education. Absent a national curriculum about the September 11 attacks, center organizers say many of its young visitors don't even know they happened. They're hoping to change that.

"The critical need for understanding, education. Who did it? Why? And how do we make it better?" said Lee Ielpi of the 9/11 Tribute Center.

A 9/11 classroom in the basement will instruct teachers on how to talk to kids about that day. Part of the lesson plan? Sometimes the best way to survive a tragedy is to turn it into something good.