Six weeks away from retiring as president and CEO of the National WWII Museum, Gordon “Nick” Mueller sat in his office above the ever-expanding Warehouse District complex, reminiscing about the journey that brought him there.

Ranked as the fourth most popular museum in the nation and 11th in the world by TripAdvisor and boasting more than 150,000 members, the museum attracts 700,000 visitors each year and has become one of the city’s most potent international attractions.

It has $110 million in construction underway or expected to break ground in 2017, and is just a few years out from fulfilling its entire $400 million master plan.

And behind the scenes, the museum’s staff of 300 and growing is embarking on a mission to become the premier center of knowledge about World War II in the country.

It’s a far cry from the humble idea conceived by Mueller's friend, the late historian Stephen Ambrose, as the two men shared a drink in the gazebo behind Ambrose’s Mirabeau Avenue home 27 years ago.

That idea — that a small piece of lakefront property should become home to a museum honoring Andrew Higgins, builder of the famous amphibious landing craft credited with helping the Allies win the war — would ultimately become the nation’s official museum dedicated to America’s role in the Second World War.

But Mueller, also a historian by training, knows there were many times the dream almost didn’t happen, saved only by hard work of the board and the generosity of donors.

“It didn’t have to happen,” he said. “It could have gone the other way.”

Those who've worked with Mueller, 77, over the years, however, point to another factor central to the museum's huge success: Mueller himself.

“Without Ambrose, you wouldn’t have a museum. Without Nick, we wouldn’t have the museum we have,” said businessman "Boysie" Bollinger, a board member since 1996 and past chairman. “He’s the force behind the strategy to build more than what we started with."

”Nick had a vision for the museum, like a prophet in a desert, or a wise man up on a mountain,” said Tom Hanks, the actor, director and producer who worked with Mueller on the museum’s 4-D film, “Beyond All Boundaries."

“For years and years, dinner after dinner, meeting after meeting, one phone call at a time, he got the place built," Hanks added. "Stephen Ambrose was the father of the museum. Nick (was) the mother, whose job it was to bear the child.”

Fell in love with history

Born in Philadelphia, Mueller grew up in Louisville, Kentucky. His father was a church historian and theologian with 300 works to his credit, and Mueller got accustomed to the habits of academic life early on, sitting around the dinner table with scholars and roaming libraries in foreign countries.

He fell in love with history as a student and later with world travel, studying for a time at the University of Vienna as he pursued advanced degrees at the University of North Carolina.

After receiving his Ph.D. in European diplomatic history in 1969, Mueller got a job teaching history at LSU New Orleans, which five years later would become the University of New Orleans. He taught there for a decade, but his zeal for travel also led him to create a study-abroad program in Innsbruck, Austria, that would become the largest summer school abroad of any American university.

The UNO chancellor recognized Mueller’s knack for creating and running programs, and his career as a college administrator began.

“Even as a young boy, my friends called me the organizer,” Mueller said. “I just liked doing that stuff, organizing people to do the things that I liked to do and was excited about.”

It was also during that time that Mueller met Ambrose, a fellow UNO historian who would soon become a best-selling biographer and author. The two men became close friends, bonding quickly over their shared love of sports, history, travel, hiking and sailing. On one occasion they retraced the entire route of the Lewis and Clark expedition.

“They were very close, like brothers,” recalled Stephenie Ambrose, Stephen’s eldest daughter.

“They were two sides of a coin,” she said. “They approached things differently, but they were on the same path.”

It was on a spring day in 1990 when Stephen Ambrose’s latest epiphany would change their lives.

“He said, 'OK, Nick, sit down. I’ve got a project for you,' ” Mueller recalled.

Always amazed that there was no museum in the U.S. dedicated to World War II, Ambrose thought some of UNO's lakefront property would be the perfect home for a small museum dedicated to Andrew Higgins.

The Higgins boat, used to storm the beaches at Normandy, had been tested on the lake. Higgins had employed thousands of workers and built 20,000 boats in New Orleans, but there wasn’t even a school or street named after him.

Ambrose said he would provide 600 oral histories and artifacts he had collected from D-Day veterans. All Mueller had to do was secure the land and raise $1 million to open the museum.

“I said, ‘That’s the best idea you’ve ever had,' ” Mueller said, before adding two caveats: “One: it’s going to cost $4 million, not $1 million — you don’t know anything about these things — and two: you’re going to be in this thing with me, because you’re the big name."

'We were going broke'

Ambrose went to see U.S. Rep. Bob Livingston, asked for $4 million in federal money and got it.

Along with UNO Chancellor Gregory O’Brien, they created the nonprofit D-Day Museum Foundation, and by 1991 they had assembled a board of trustees.

Mueller and Ambrose began beating the bushes to raise money to build what was now conceived of as a museum to honor D-Day, the Allied invasion of Normandy in June 1944.

Ambrose used his fame to open doors, Mueller his persuasive powers to convince potential donors that it wasn’t crazy to give two history professors money to build a war museum.

Four years later, Mueller recalled, “we were going broke.”

“We made a lot of mistakes along the way," he said, one of which was holding on for too long to the idea of building the museum on the lakefront, despite a strong sentiment from the board that downtown was the logical choice for a museum looking to attract visitors.

With time running out on the $1 million they had left from the original federal grant, the board made a move on an old warehouse near Lee Circle.

“It broke the logjam,” Mueller said. “We had to show something. We had an Oscar-nominated film, 'D-Day Remembered.' … We had $300,000 worth of artifacts that we purchased for the museum in Normandy, and that big hulking warehouse.”

But the difficulties continued. Fundraising wasn’t going well, the foundation was spending too much money on consultants, and the board was losing members.

Mueller was on sabbatical, preparing to go back to teaching after 20 years in administration, when he was “ambushed” by Ambrose and O’Brien at one of the board’s committee meetings. They wanted him to become chairman, effectively taking the reins of the operation full time.

It wasn’t an easy decision, and it took him several months to make it, but Mueller put his other plans aside and took the job, pledging to open the museum by the 56th anniversary of D-Day in 2000.

“It was a race to the finish line, I’ll tell you,” Mueller said. “But we got after it and we raised the private money, and we met our grand opening deadline.”

On June 7, 2000, the day after the event, U.S. Sen. Ted Stevens arrived for a tour. The Alaska Republican had fought against the Japanese and loved what he saw at the museum. He wanted more of it.

The powerful chairman of the Senate Appropriations Committee, Stevens told Mueller and Ambrose he could get the museum significant funding if they would expand the scope to encompass the entire war, and that he could get it a national designation.

“Ambrose gave me that look — ‘No more fundraising, please!’ — but what else could we say?” Mueller recalled. “I just thought, we can’t let this opportunity walk out the door with a no,” he said. “It will never happen again.”

A daunting task

Mueller said that while the D-Day Museum had a tight, narrative focus, the decision to tell the entire story of America's role in a war that was a global, transformative event was daunting.

Mueller, Ambrose and the board began the process of buying land, creating a $280 million master plan and hiring national consultants. Ambrose died of lung cancer in 2002, but the work continued, and the fundraising struggles of the 1990s were in the past.

Even after Hurricane Katrina, Mueller and the board held to their course, making only minor adjustments to the plan — a leap of faith considering that attendance had plummeted.

Visitation was down 40 percent in 2009 from pre-storm numbers, but the opening of "Beyond All Boundaries," the 4-D film that Mueller worked on with Hanks and consultants from the Hettema Group, caused it to double overnight. It's been climbing ever since, said Stephen Watson, who joined museum staff 15 years ago and will take over for Mueller in July.

Bollinger said Mueller’s deep involvement in the entire process — the museum’s content, the design of the campus and its buildings — cannot be overstated. He said the museum’s emphasis on telling the story of the war through the voices of its soldiers came from Ambrose, while Mueller brought the emphasis on scholarship and historical fidelity by involving consulting historians.

“There’s nobody who understood what Steve was trying to accomplish better than Nick," he said.

In the "Road to Tokyo" exhibit, the voice of soldier Richard Greer describing the moments before an oncoming bayonet attack came from an interview conducted by Mueller.

Sitting at his desk last week, Mueller choked up describing the account of a medic who swam ashore at Normandy and had to scavenge dry bandages from dead bodies, haunted by the faces of the dead as he tended to the wounded.

“What this museum is all about is saving the history of those guys who are beneath tombstones,” Mueller said. “That is at the core of what we do here. Understanding what they did and their character creates the moral compass for our country for the last 75 years.”

Mueller said the emphasis on the personal — the dog-tag experience that lets visitors follow the story of individual soldiers, and the notes and artifacts that fill the exhibits — creates an important connection:

“If we’re successful, it should speak to people’s beliefs and their values. A lot of people say, ‘I wonder if I could do that?’ And then you know that you’ve grabbed them.”

In addition to the boats, planes and tanks on display, the dog-tag experience, the 4-D movie and dramatic "Road to Tokyo" and "Road to Berlin" exhibits, the museum even has a working PT boat in the water at Lake Pontchartrain and puts on an air show.

“I don’t know if this community understands the significance of the impact (Mueller) has had on this museum and that this museum has had on this city,” Watson said.

Patrick Gallagher, a national consultant who worked on the plans as the museum expanded its focus, said museums have come to rely on TripAdvisor to gauge how they are viewed by the public, and he called the WWII Museum’s consistently high ranking “astonishing” because it’s a history museum.

“They tend to have lower rankings because the techniques people use have been pretty traditional. Nick really pushed this one out of the box," he said. "You can’t walk out of there without feeling like you have been touched on every level.”

'Letting go ... is tough'

Mueller will stay on as president and CEO emeritus and will remain active with the museum, primarily through the nascent Institute for War & Democracy that he's setting up. Its staff of eight will focus on retaining the historical integrity of the museum’s exhibits, programs and publications.

“We have got to be the source of the best knowledge of World War II for the public memory of this nation,” he said. “We need that core.”

Mueller is also excited about another initiative ramping up, the Media & Education Center, which will have a team focused on media production, distance learning and using digital content from the museum’s collection to support teachers, students and other audiences.

His part-time role will free up time to spend with his wife, Beth, and to travel, speak, write and do “some of the things I’ve put on the back burner all these years.”

He is also planning on writing a book about the museum’s history.

But with plans for the future Bollinger Canopy of Peace, Higgins Hotel and Conference Center, Hall of Democracy and Liberation Pavilion already mapped out, Mueller said it’s a good time to step aside.

“Letting go of it, it’s tough,” he said, his voice cracking again. “It’s sorta like raising kids. You get them to their teenage years … and you gotta say, ‘You’re on your own now.’ The end has to come somewhere.”

Follow Chad Calder on Twitter, @Chad_Calder.