If it weren't for two years of unwanted litigation, the long-awaited Four Seasons Hotel and residences at the foot of Canal Street might have celebrated a grand opening Wednesday instead of a groundbreaking.

Instead, the developers behind the nearly half-billion-dollar project invited hundreds of local officials and business leaders into the lobby of the former World Trade Center Building, a 33-story 1960s office tower that has been vacant for years but was dressed up for the occasion.

White curtains lined the first-floor windows and covered the nonfunctioning escalators and the building’s white marble background where a stage was set up.

Visible signs of progress have been slow from the building’s exterior but are expected to become more obvious in coming weeks, when an exterior construction elevator is erected to allow crews access to the top, where they will begin interior demolition and remediation work.

The 341-room hotel, bearing one of the world’s most prestigious brands, plus 90 high-end luxury condos are now scheduled to open by late 2020.

Wednesday’s groundbreaking was also the latest stop on Mayor Mitch Landrieu’s victory lap, with just a few days to go before his term ends Monday, and on the ongoing celebration of the city’s 300th birthday.

Can't see the video below? Click here.

When the Four Seasons opens, it will be a significant piece of New Orleans’ recent construction boom, which has included construction or conversion of nearly two dozen hotels in recent years as the city's tourism numbers have grown.

Paul Flower, president and CEO of co-developer Woodward Interests, described the Four Seasons project, budgeted at $460 million, as the “largest private investment this city has ever seen.” It’s expected to generate $15 million in annual property and hotel tax revenue for the city and state.

Once it’s complete, the building will boast two signature restaurants and more than 20,000 square feet of event and meeting space, as well as an observation deck in the two-story rooftop cupola that will offer panoramic views of the city and river.

Taking a congratulatory tone similar to when he spoke last week at the groundbreaking for the city’s new $1 billion airport terminal, Landrieu touted the Four Seasons as encapsulating the city’s recent upward trajectory, bringing back a once-iconic building that, despite being located on prime riverfront real estate, has been unused for years.

Now, he said, it's slated to be transformed into one of the world's top-line hotel brands, a narrative that fit with his regular refrain about overseeing the city’s rebuilding not in the way it was before Hurricane Katrina, but “the way it should have been had we gotten it right the first time.”

Among the others who addressed the crowd Wednesday was Dick Friedman, CEO of Carpenter & Co., the project’s Boston-based master developer who is also a director of Four Seasons Hotels and Resorts.

Most of the money being used to finance the project is from overseas, he said, describing it as a remarkable accomplishment that represented confidence in the city’s leadership.

“We will build this 50-year-old building for the next 100 years,” he said, calling it “a fantastic project” that, once completed, will be the grandest residential hotel project “within 500 miles of where we sit.”

For years, construction was held up by litigation filed after Carpenter and Woodward beat out proposals from four other teams in early 2015 for the right to reach a deal with the city, which owns the building.

One of the losing development teams, Two Canal Street Investors, sued, claiming that the city's decision violated public lease law requirements, lacked transparency and was fraught with political influence and favoritism.

The lawsuit sought to reverse the city's decision and award a lease to Two Canal, or at least to toss out the Four Seasons deal.

A Civil District Court judge eventually ruled in the city's favor, and last year, the Louisiana Supreme Court declined to hear the matter, clearing the way for work to move forward.

Under the 99-year agreement signed by Landrieu, the developers will pay the city $3.25 million per year in rent for the first 10 years of the lease, $3.75 million annually for years 11 through 20 and, after that, an amount equal to the base rent for the preceding five years times the percentage increase in the consumer price index for that period.

Follow Richard Thompson on Twitter, @rthompsonMSY.