An 80-storey office building set to open this week at the World Trade Center will be the third completed skyscraper at the site where the twin towers stood.

Monday’s ribbon-cutting for the 1,079-foot (329-meter) 3 World Trade Center marks a major step in the rebuilding of the site, stalled for years by disputes among government agencies, trade center developer Larry Silverstein, insurers and 9/11 victims’ family members who wanted the entire site to be preserved for eternity as a memorial.

The new $2.7 billion building, designed by Pritzker Prize-winning architect, Richard Rogers has been the fifth-tallest building in New York City since its construction commenced in 2016.

That designation seemed elusive in 2009 when the Port Authority of New York and New Jersey, which owns the trade center site and was battling with Silverstein over costs associated with rebuilding, sought to reduce 3 World Trade Centre to a four-storey “stump.”

After arbitration in the dispute between the developer and the property owner, construction started in 2010 but was halted at seven stories due to a lack of financing.

Three World Trade’s 62-foot (19-meter) lobby faces the National Sept. 11 Museum. Wedged between the Santiago Calatrava-designed transportation hub and 4 World Trade Center, also built by Silverstein, the new building consists of an 80-storey tower straddling a 17-storey podium.

The skyscraper boasts of an annealed glass exterior with 10,000 glass panels that have been cooled slowly to reduce internal stress, meaning the glass shouldn’t break into shards if it is struck.

Inside, office space is being readied for anchor tenant 3M, an advertising firm, with exposed ceilings with outdoor terraces on the 17th, 60th and 76th floors including an outdoor deck that will be shared by all the building’s tenants.

With a mural of a dancer in a red dress adorning a wall on the otherwise bare 68th floor, the new building becomes the second Silverstein skyscraper to feature graffiti artists’ work.

The still unfinished 2 World Trade Center, immediately north of the transportation hub, is awaiting an anchor tenant and financing before it can be built beyond a stump

Also starting construction after years of delays is the nearby Ronald O. Perelman Performing Arts Center at the World Trade Center, named after the billionaire investor after he made a $75 million donation. Its scheduled completion date is 2020.