NEW YORK (CBSNewYork) — The largest and most expensive private real estate development in U.S. history is being built on the west side of Manhattan.

It’s called Hudson Yards.

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On Wednesday, the centerpiece of the project was topped out.

CBS2’s Kristine Johnson was given an exclusive tour by the man behind it all, mega-developer Stephen Ross.

“You kind of look at it, it’s kind of like, what is that?” Ross said.

It’s New York’s latest urban landmark known as The Vessel.

“It’s 150 feet, it’s a 15 story building,” he explained.

Wednesday morning, after eight months of construction, the last structural piece was installed.

“The Vessel itself was $150-million,” Ross said.

Developer Stephen Ross said over and over again, he was told it couldn’t be done.

“Some people thought we were crazy to do it, and spend that kind of money on a piece of art, but it really shows you what this project really is,” he said.

The centerpiece of the Hudson Yards Public Square and Gardens. The Vessel is comprised of 154 intricately interconnecting flights of stairs, 2,500 individual steps, and 80 landings.

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When you take all of the steps it’s a one mile walk.

“The whole way, and then down,” Ross said.

Created by Thomas Heatherwick and Heatherwick Studio, the Vessel is comprised of 75 enormous pre-fabricated pieces made in Italy.

Assembled with geometric accuracy, the new kind of vertical space will offer some of the most unique views of the West Side.

“This didn’t exist. This was train tracks that we’re standing on,” he said.

Built on top of an existing rail yard, the Hudson Yards project is being called a city within a city. It’s home to more than 100 shops and restaurants, thousands of new residencies, a school, a hotel, and 14 acres of public open space.

When it opens in early 2019, The Vessel will be free to the public who will eventually be asked to re-name the installation.

Ross said he has some ideas in mind, but wouldn’t say what they were. He likened the large scale work of art to the Eiffel Tower, only better.

“It’s a great legacy to be able to do something like this,” he said.

Just like the Eiffel Tower, the vessel will be lit up at night.

Speakers will be installed so music can be played inside, and it’s expected there will be a lot of marriage proposals taking place.

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