Dallas, Texas, is prepped to become one of the “greenest” cities in the United States. The city is building a 10,000-acre nature district along the Trinity River, and the $600 million park will be more than 11 times the size of New York City’s Central Park.

Designed by Michael Van Valkenburgh Associates, the Trinity River Park hopes to transform a Dallas floodplain into a lush recreation space. The project is focused on two goals: cultivating civic spaces and improving the natural landscape. The civic spaces—playgrounds, fountains, plazas, and lawns for picnicking—aim to connect the city with the river. Organizers also hope that the park will bridge the gap between the city’s poorer southern sector and the wealthier north.

The landscape design, on the other hand, wants to protect the city from extreme flooding by using riparian vegetation to restore the river’s ecological function and natural beauty. According to Michael Van Valkenburgh Associates, the park will be accessible even during 10-year storms. All sports fields and paved trails will be elevated and located farthest from the river. Five bridges will connect the park to the city center.

Voters first approved a Trinity River Park in a 1998 bond referndum, but the project has been tied up in red tape ever since. According to the Dallas News, the project received a recent boost in October 2016 when Annette Simmons—the widow of billionaire Harold Simmons—donated $50 million to help fund 285 acres.

This particular section of the park will be called the Harold Simmons Park and is set to be complete by 2021. Taken together, the larger nature district has been ongoing since the early 2000s, with over $609 million being spent on trails, a bridge, a horse park, golf course, and community center.

Some question whether the new park will in fact be flood-proof. Before the new sections of the park break ground, the U.S. Army Corps of Engineers will need to approve the plans.