William Ahearn will never forget what it was like on the streets on New York on Sept. 11, 2001.

"The one thing that got me, it smelled like Vietnam," said the retired firefighter. The visceral memory of the hours after the towers fell still weighs on him.

Ahearn is one of the owners of Suspenders Bar. Fifteen years ago, it was located on Broadway, just a few blocks from the World Trade Center. When the towers came down in the attacks, thousands of volunteers from across North America came to New York to help sift through the rubble. Suspenders became their second home. 

Willaim Ahearn headshot

William Ahearn, co-owner of Suspenders Bar in New York City, remembers the first responders who made the spot their second home during recovery efforts at Ground Zero. (Steven D'Souza/CBC)

"We were closed as a crime scene but we literally broke the chains with bolt cutters and invited all of these people that were sleeping on the streets to at least sleep on the floor of the restaurant," Ahearn said, seated at the bar's new location, still in the shadows of Ground Zero.

For Ahearn the 15th anniversary of the attack is a chance to remember the victims, to thank those who helped and to show the city's resilience.

Oculus at World Trade Center

The Oculus is the newly opened entrance to the Westfield World Trade Center mall beneath Ground Zero. (Steven D'Souza/CBC)

"We weren't destroyed after the '93 (World Trade Center) bombing, we weren't destroyed after this one," he said.

The emotional recovery from 9/11 is still very much a work in progress for many New Yorkers, a process that mirrors the physical transformation of the site itself.

The 9/11 Memorial park opened in 2011, and the One World Trade Center tower opened in 2014. The tower has instantly become an iconic part of the city's skyline, enshrined in souvenir kitsch in everything from paperweights to calendars to magnets. 

The Perelman Center

An artist's rendering shows the Ronald O. Perelman Performing Arts Center, slated to open in 2020 beside the World Trade Center. (Luxigon Digital Renderings)

In August a mall opened beneath the complex with a stunning entrance called the Oculus. A new transit hub connects the site to all corners of the city. The area has become a must-see on any tourist to-do list.

The community around the World Trade Center is also undergoing a renaissance. There are now 29 hotels in the area, compared to just six in 2001. More than 60,000 people live in neighbourhood now, triple the number in 2000.

But for all of the improvements, Ground Zero itself is still a construction site. Visitors must navigate their way around construction fencing and along temporary roadways. Two buildings are under construction, and last week the design for the long-delayed Ronald O. Perelman Performing Arts Center at the site was finally unveiled.

"What you have is a testament to life, to hope and to the desire to live in the best possible environment that we can create," said developer Larry Silverstein at the launch of the centre.

Designed by New York-based REX Architecture, the building will sit beside the One World Trade Center and will be wrapped in translucent marble, allowing light to shine out at night and giving the building an amber glow. 

Famed architect Daniel Libeskind, who created the master plan for the site in 2003, says the area has lived up to goals he set out.

"The aim of the project is to show the victory of life over the evil deeds that befell New York," he said.

"It is a space that has the dignity of memory and a record of what has been. It pays homage to those who fell, but at the same time it's a picture of liveliness and the beauty of diversity and freedom of New York."

Back at Suspenders, Ahearn is expanding the new location to include two floors. Eventually he'll put back on display all the pins, patches, pictures and letters he received from the first responders who visited the old location.

He says the resurgence of the neighbourhood is one more step in the long road to recovery for New Yorkers.

"We don't quit. You can knock us down, but we get up, and we got up with the help of the entire world."