Dec. 18: On Brad Pitt's 50th birthday, a look at his passion project in New Orleans

Brad Pitt, actor, producer, celebrity, father, philanthropist, activist, turns 50 today.

He's known around the world for his films, but for people in New Orleans, he's known for quite a bit more. Pitt and his nonprofit, the Make it Right Foundation, have been building sustainable, low-income homes in the city's Lower Ninth Ward since 2007.

It's been his pet cause for the past six years. Two years after Katrina destroyed most of the homes in the Lower Ninth Ward, Pitt toured the area and was appalled with what he saw.

"I met Katrina victims who had been given FEMA trailers and had nothing to hook them up to," he told USA Today in 2010. "Others had formaldehyde problems. What was the message? We were telling people to come home and yet when they got back to New Orleans they were treated in a substandard way. I just thought it was atrocious."

The admitted architecture junkie and environmental activist decided to combine his passions to help the people of the Lower Ninth rebuild. He pledged to build 150 homes specifically for those residents that were both sustainable and more stormproof. He enlisted eco-friendly builders and world-renowned architects, including Frank Gehry and Hitoshi Abe, to help out. The homes are instantly recognizable—they are elevated on stilts and include modern minimalist design touches like bright colors and unusual angles.

He raised millions of dollars to fund the project and has since built about 90 homes at a cost of about $180,000 to $430,000 each. Former residents of the area can purchase the homes for between $150,000 and $200,000, but they may also qualify for subsidies.

The work that's been done there has been personally touching, he told the "Today" show in 2008.

"It's an incredible feeling to see them picking their rooms, they're fighting about who's going to get what room," he said of meeting residents. "I see the upbringing they're going to have there, the experiences, the memories they're going to have in this place."

Despite the work he's done getting families back into homes in their historic neighborhood, Make it Right has recently come under fire for its approach to helping the people of New Orleans. A recent article in the New Republic sparked criticisms that he picked a spot that simply won't come back to life because it lacks access to essential stores and services, that more could be done for the cost of the homes and even that their design aesthetic doesn't match the low-income area.

The foundation has also moved away from its mission and opened up the homes to people from outside the neighborhood.

But that's not stopping Pitt (and he has his fair share of defenders as well). He's expanded the foundation to include sustainable apartments for disabled veterans in Newark, N.J., and eco-friendly housing in blighted areas of Kansas City and Fort Peck Reservation in Montana.

"There's no end to what we can do," Pitt told Jon Stewart in 2012.

Ilyce Glink is an award-winning, nationally syndicated real estate columnist, blogger and radio talk show host, and managing editor of the Equifax Finance Blog. Follow her on Twitter @Glink.

On This Day, previously:

Nov. 25: The only house that JFK and Jackie ever built
Nov. 22: A peek at Scarlett Johansson's modest and fancy homes
Oct. 8: A look at Matt Damon's house on his 43rd birthday