Construction on a massive waterfront residential development started Monday on what is being called one of the biggest private investments in the history of the Bronx.

Workers have begun building the first floor of three towers, which will all be connected and overlooking the Harlem River.

Seven towers and more than 1,300 apartments are being built on each side of the Third Avenue Bridge. Brookfield Properties developed the nearly $1 billion project. It will feature a public waterfront park and promenade- allowing access to Mott Haven's waterfront for the first time in more than a century.

A tech-based community and 15,000 square feet of local retail is also part of the plan. Developers say many of the construction workers are local hires.

"We knew that this was going to be a game-changing and impactful investment in the Bronx, and we wanted to make sure it was not just -- that the Bronxites themselves would benefit from that investment," said Charlie Howe, project manager at Brookfield Properties.

Developers say 30% of the apartments will be affordable through the Affordable Housing New York Program. Community members say they hope rent rates are actually fair.

Phase one of the project, which is the construction of the three towers, is projected to be finished by the start of 2022. Phase two, the construction of the other four towers, is scheduled for a 2023 finish.