The new Anderson Pavilion at Children's Hospital Los Angeles cost $636 million and is 460,000 square feet, which is the equivalent of 100 NBA basketball courts.
The first patient to make the move was 10-year-old Manny Hernandez III.
Manny's dad was across town working on another hospital construction site, but his heart was with his son.
Manny Hernandez Jr., known to his friends as "Big Manny," worked on the new building for four years. During that time, his son practically lived at the hospital due to a rare blood disorder that cripples his immune system. Any cold is life threatening.
"It's just been hard as a parent. You see your son at night waking up every hour in pain," Hernandez said. "Nurses come in and comfort him."
Manny's sister had heart surgery at the hospital as an infant.
The family feels they owe a lot to Children's Hospital, so when Manny's dad was offered the opportunity to work there, not only did he pick up the job, he contributed all his overtime pay to the project.
"I don't have the resources like a lot of other donors, but at least I could give something," Hernandez said. "It would be the greatest thing to pay back for what they did for my daughter."
When work got difficult, thinking about how hard the hospital staff works on treating children inspired Hernandez and the rest of the crew.
"The guys would say, 'Well, we're doing this for the children,' and they team up and they get it done," he said.
Manny said he is proud of his dad's work.
"I think that's pretty amazing and awesome," he said.
His dad can't think of the new building without getting choked up.
"I could say hey, I worked on that, you know? I made a little difference," Hernandez said.
Manny said he loves his new room. It has a computer, work station and pullout bed for his family. He can even play video games, talk to doctors via the Internet and order food.