The first rehabbed building in Ford Motor Co.'s new 30-acre Detroit mobility district is now filing with workers and ready for an official public unveiling.

The Albert Kahn-designed Book Depository, 2050 15th St. in the city's Corktown neighborhood, which first opened in 1936 as a U.S. Post Office and later was a warehouse for Detroit Public Schools, has undergone a dramatic redevelopment and redesign into modern workspaces and studios for mobility-focused companies and technologies.

The three-story, 270,000-square-foot building had sat unused for about 30 years until Ford bought it in 2018 from the Moroun family.

The building neighbors the massive Michigan Central Station that Ford also is redeveloping. The former train depot will be the centerpiece of Ford's new Michigan Central mobility district campus once work crews finish it in early 2024.

On Tuesday afternoon, Bill Ford, the automaker's executive chair, is expected to join a special event to celebrate the Book Depository's reopening.

"This is the first very big step for us," Michigan Central CEO Josh Sirefman said, "but it’s one piece of ultimately a bigger picture."

One of the most stunning additions to the Book Depository is an enlarged central atrium that extends through all three aboveground floors and also features a new floating staircase. The original atrium was much smaller and extended only to the second floor.

And in the basement level, a tunnel that had connected the building to rail lines behind Michigan Central Station has been redone and reactivated.

In partnership with Ford, the Book Depository is now home to the first Detroit office for Newlab, a collaborative workspace environment for young companies that started in Brooklyn, New York, in 2016.

Newlab earlier this year began occupying the Book Depository and so far has attracted 150 members from more than 25 companies to the building, of which about half are new to metro Detroit. While the building is now mostly done, work crews still have a few small touches to finish by this summer.

More: Newlab at Michigan Central is for startups working toward a future of mobility

More: Newlab at Michigan Central is for startups working toward a future of mobility

"The entirety of the building will be filled with those who are working at the intersection of mobility and society," said Michigan Central's Head of Place Melissa Dittmer. "They could be technologists, they could be makers, industrial designers, companies focused on mobility solutions."

Ford is not disclosing cost figures for the Book Depository rehab. The automaker last reported total anticipated costs for its Michigan Central project at $950 million.

Roosevelt Park annex

The building was the Roosevelt Park annex of the U.S. Post Office from 1936 into the 1960s.

During an era of widespread racial discrimination, jobs in the building were particularly desirable among Black Detroiters. Past employees of the Roosevelt Park annex included future Detroit Mayor Coleman Young, who worked there for six months in 1941, before he was fired for union organizing, according to Free Press archives.

More: Police target distracted drivers in metro Detroit

More: Birmingham set to pass watered-down ordinance on renters' rights

In 1966, the federal government sold the building to Detroit Public Schools for $10,000. The building was used for storing schoolbooks, supplies and district records, and became known as the Roosevelt Park Warehouse.

The district stopped using the building after a March 1987 fire that severely damaged the interior.

The empty warehouse was back in the news in 2009 when a group of urban explorers discovered a dead body that was partially encased in ice in an elevator shaft.

By the time Ford acquired the building, the old DPS records and schoolbooks were long gone, although some large machinery and conveyor belt equipment was still inside and needed to be disassembled before it could be removed.

"This was a beast of a building that could handle just about anything," Dittmer said. “So it went through a fire, it went through decades of vacancy and the bones still here.”

The architect for the redevelopment was Gensler and New York-based Civilian did the interior design.

Today, Kahn's signature "martini glass" steel-reinforced concrete columns are exposed and visible throughout the building. Besides the expanded atrium, other new features include coworking spaces, privacy booths and a cafe and cafeteria.

There also is nearly 11,000 square feet of workshop space available for Newlab's occupants.

"There’s everything within this facility for those innovators and makers to figure out how to bring their inventions and mobility solutions forward, and then to scale up their business," Dittmer said.

Contact JC Reindl: 313-222-6631 or jcreindl@freepress.com. Follow him on Twitter @jcreindl.

This article originally appeared on Detroit Free Press: Ford to unveil rehabbed Book Depository in Detroit