 -- It's finally done.

Thirteen years after the Twin Towers were destroyed on Sept. 11, 2001, the new centerpiece skyscraper at the World Trade Center opens this morning.

The path to this day was anything but easy or clear. Battles began almost as soon as the debris was hauled away in 2002 and, since then, there have been fights over cost, design, security and even the structure’s name. But still, the tower – a technological marvel sitting on piles driven more than 100 feet below the Hudson River – rose steadily out of the northwest corner of the WTC site.

Today, the storied Conde Nast magazine empire, with titles like Vogue, GQ and Vanity Fair, moves in with 2,300 employees spread among 24 floors. In so many ways, this day marks the final piece of the rebirth and renewal of a Lower Manhattan devastated when two hijacked jets slammed into the Twin Towers that bright morning.

On Sept. 11, 2011, the 9/11 Memorial opened. Six months ago, the 9/11 Museum opened. Both were built to commemorate what was lost.

One World Trade is a monument to the future.

“It’s a fantastic milestone,” said Steve Plate, who has overseen WTC construction since the beginning. “I was there that fateful day. And to see from where we started to where we are today, it’s truly a miracle.”

“It truly is the eighth wonder of the world,” Plate said. “And the building itself is truly iconic.”

The new 1 WTC tower and the 16-acre site it anchors are owned by the Port Authority, a massive government agency controlled by the governors of New York and New Jersey.

Plate was supposed to be in his office on the 82nd floor of the North Tower when the attacks began 13 years ago. He wasn’t because he drove his son to school and then missed his usual train. Since then, it has been his mission to rebuild the site into something that would make New York City proud.

“I’m an engineer and I can add numbers and tell you ‘tallest, strongest’ and all this stuff,’ Plate said. “But at the end of the day, it’s the most beautiful building in the most beautiful city in the most beautiful region in the world.”

Standing at 1,776 feet (which includes its landmark spire), 1 WTC is the tallest building in the country and the western hemisphere. It is 104 stories tall and has a three-floor observatory that is to open this spring.

Much like the tower itself, its price tag rose steadily since construction began. By the time the first Conde Nast employee walks in today, the final dollar figure will be around $3.9 billion – or double the original estimate.

The problems and battles that preceded today are going to fade into the background, according to the building’s boosters, as 1 WTC takes its place in the fabric of New York.

“There’s so many people who have done so much to bring it where it is,” said Dave Checketts, the CEO of Legends, the company operating the observatory on floors 100-102, told ABC News Anchor Dan Harris. “I give them all a lot of credit for staying with the fight because the finished product is going to be something inspirational to people and comforting.”

Checketts said there’s just one message in the reality that the new skyscraper is built and reclaiming its place near the southern tip of the New York skyline.

“It’s a brute fact. We did come back,” Checketts said looking out from near the tower’s top. “We brought it back; we built it even higher than it was before.”