Vessel—Thomas Heatherwick’s ongoing public project in New York City’s Hudson Yards development—topped out this week during its eighth month of construction.

Besides being “one of the most complex pieces of steelwork ever made,” according to its British designer, the developers behind Hudson Yards are touting Vessel’s completion as “an undeniable exclamation point” for the new area.

The skeletal tower is a vertical public park made up of upward spiral of stairways and landings that, if unstacked from their 16-story structure, would measure about a mile in length. Heatherwick’s design was revealed in fall 2016 and construction began months later in April 2017.

The prefabricated steel pavilion was manufactured in Italy as a series of 75 pieces. After being shipped to Manhattan, they were assembled on site into a 150-foot-tall edifice and clad with polished copper. According to Heatherwick, construction is running ahead of schedule and the prefabricated pieces fit together with an “astonishing geometric accuracy.”

Currently, Vessel is slated to open in early 2019. Heatherwick explained the next year would be spent installing “the final details of the structure” including paving, balustrades, and lighting, as well as the landscape elements of the surrounding plaza, which Heatherwick Studio and Nelson Byrd Woltz Landscape Architects are jointly designing. The roughly five-acre public space will run through the entire Hudson Yards development and connect to the High Line.

Video courtesy Related Companies