A vibrant landscape of hilly grasslands and creeks at the edge of New York City was once Fresh Kills, the massive, stinking dump for Gotham's garbage.

Today, the 2,200-acre site on Staten Island is on its way to becoming Freshkills Park, the largest landfill-to-park project in the world.

The park will be three times the size of Central Park. It will be fully completed by 2035, but some sections are already available to tour groups and schools.

This month, 700 acres opens to the public for one of the park's triennial "Discovery Days" for nature walks, biking and kite-flying.

Seagulls that once fed on 150 million-tons of household trash are gone, replaced by nearly 200 species of birds.

Much of the park will remain passive with trails and wildlife habitats.