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A smoldering lower Manhatten is seen at dawn in this Sept. 15, 2001, photograph. Work to rebuild the World Trade Center complex destroyed in the Sept. 11, 2001, terror attack remains incomplete.

NEW YORK — Two decades after its destruction in the Sept. 11 attacks, the work to rebuild the World Trade Center complex remains incomplete.

Two planned skyscrapers, a performing arts center and a church are still unfinished at the site, which plays host Saturday to the annual ceremony honoring nearly 3,000 people killed in the attacks.

Visitors to the commemoration will find a place that no longer has the feel of a construction zone, though, even as the work continues.

The memorial plaza with its twin reflecting pools opened in 2011. One World Trade Center — the spire originally known as the Freedom Tower — opened in 2014, as did the National Sept. 11 Memorial and Museum. An underground transit hub and shopping mall opened in 2016. Three other glassy towers built to replace those lost in the attack are open.

Cranes and construction fences, however, can still be seen around the site. Here is a look at the unfinished work:

2 World Trade Center: Planned as the second tallest skyscraper at the site, 2 World Trade Center might someday reach 80 stories. But for now, just a low stump of a building exists as a placeholder, covered with colorful graffiti-style murals at the northeast corner of the Trade Center site. Developer Larry Silverstein has said he wants to sign an anchor tenant for the tower before starting construction.

Performing arts center: After years of delays, the Ronald O. Perelman Performing Arts Center is under construction just to the west of 2 World Trade Center’s future site and is scheduled to open in 2023. While a performance center was part of World Trade Center master planner Daniel Libeskind’s original scheme, disputes over its budget and design with project architects threatened its viability in the years. In 2015, the center’s leaders announced a new team of architects, who have designed a translucent glass and marble cube.

Greek Orthodox church: The long-delayed construction of the St. Nicholas Greek Orthodox Church and National Shrine, replacing the only house of worship destroyed in the attacks, is now proceeding briskly after years of delays. Slated for completion next year, the building is going up near the southeast corner of ground zero and will look down on the memorial plaza from a perch atop another building that holds the entrance to the World Trade Center’s underground garage.

5 World Trade Center: Construction has yet to begin on the tower that will replace an office building, occupied by Deutsche Bank, that was damaged and contaminated by debris from the collapsing twin towers. The original building was demolished between 2007 and 2011. In a project that could be complete in five years, the now-cleared site will have a 900-foot tower with office and retail space in addition to 1,325 apartments.