With little fanfare, crews recently broke ground at “The 78,” a massive development replacing a 62-acre vacant lot along the Chicago River’s south branch.

Last week, crews operating half a dozen bulldozers were digging through patches of soil on the northwest side of the site adjacent to the river. The work is significant because it marks the initial phase of the construction of mixed-use megadevelopment as well as the final stage of the Wells-Wentworth Connector project.

In April, the city council approved Related Midwest’s $7 billion mixed-use megadevelopment—an ambitious plan to construct 13-million square feet of new residential, commercial, and retail space, a public-private research center, and a seven-acre crescent-shaped park.

As part of the project, the city approved a $700 million subsidy in the form of a tax increment financing (TIF) district to pay for infrastructure improvements in the neighborhood, including $364 million for the new Red Line station, the relocation of Metra tracks, and improvements on Clark Street.

The Wells-Wentworth Connector, the new road will directly connect the Loop and Chinatown by roadway for the first time, is another key part of The 78’s infrastructure. Related says it expects the work to be completed by the end of 2020.

Related 11 megadevelopments that will transform Chicago

Both The 78 and the connector project have been a long time coming.

A Chinatown-to-downtown roadway was proposed by Daniel Burnham’s famous 1909 Plan of Chicago, and officials have talked about the need for it ever since. “It cannot be emphasized too often that a new outlet southward from the Loop is one of Chicago’s most urgent needs,” said mayor William E. Dever in 1926, according to the Tribune.

In 1929, the city straightened a crooked bend in the Chicago River to better connect the south side to the downtown street grid. But the road was never built. Instead, it became a site of railroad infrastructure connected to Grand Central Station, a former passenger railroad terminal on West Harrison Street. The terminal became defunct in 1969 and the 62-acre lot had remained dormant for fifty years.

Former Mayor Rahm Emanuel brought the connector plan back to life in 2014 along with an announcement that Related Midwest had acquired the brownfield site and intended to develop it.

Construction began on the first phase of the connector—primarily involving rebuilding Wentworth Avenue between 17th and 19th Street—began in 2016 and was completed the following year. The second phase of the project, also currently in progress, will realign Wentworth Ave. between Archer and Cermak, while also eliminating one of the most dangerous intersections in the city.

Work on the final phase of the connector is a collaboration between Related Midwest and the Chicago Department Transportation. When it’s finished, car, foot, and bike traffic will be able to travel from Roosevelt to Cermak Road on an extension of Wells Street to Wentworth.

The developer says that the new parkway “sets a new precedent for streetscapes in the city” due to features like elevated bike lanes separated from the road and sidewalk by trees and plans and additional lighting for pedestrians beyond street lights. “[It] will create an aesthetically pleasing, multi-tiered space that illuminates the entire sidewalk, bikeway and landscape,” said Related Midwest.

Related did not comment on a timeline for the completion of The 78.