You can see the stark difference between this August 30, 2001 photo and a photo taken from the spot 16 days after the attacks. It would take several months for rescuers to go through the rubble.
In December 2003, a design for the new One World Trade Center was finally unveiled.
In addition to the 1,776 foot One World Trade Center building, the site would also come to include four other World Trade Center buildings, a 9/11 Memorial and Museum, the Ronald O. Perelman Performing Arts Center, a WTC Transportation Hub, and Liberty Park.
Sources: New York City Port Authority, Curbed
But about four years after the unveiling, the site still looked about the same, as construction was hamstrung by lawsuits, budget overruns, design changes, and a recession.
Source: Time
By July 2011, the memorial waterfalls were being tested, and One World Trade Center's facade was beginning to reflect the sky.
Here's the Manhattan skyline in August 2011. You can see the unfinished tower beginning to peek over the other skyscrapers.
The memorial waterfalls officially opened in September 2011, and the museum, seen on the right, opened in May 2014.
By November 2014, One World Trade Center was completed, as was 4 World Trade Center (left) and 7 World Trade Center (right.) But 3 World Trade Center, seen here with the crane above it, still wasn't finished.
The WTC Transportation Hub, on which the soaring white Oculus was built, was also under construction in late 2014.
The $50 million Liberty Park also opened in June 2016. From there, visitors can get an overhead view of the Ground Zero memorial.
Source: Gothamist