WASHINGTON — City leaders presented six possible ideas for redeveloping the 190-acre site where RFK Stadium and the D.C. Armory sit today.

The renderings were revealed Monday night at a community meeting at the Washington Convention Center.

“This is a once in a lifetime effort to re-imagine this site,” said Max Brown, board chair for Events DC, which operates the site along with the convention center and Nationals Park.

There are two main concepts — the North-South Axis Concept and the Stitch Concept.

Each includes three long-term options: A 65,000-seat NFL stadium which could bring the Redskins back to D.C., a 20,000-seat arena for use by the Capitals and Wizards, or neither.

In addition, numerous short-term projects were presented that could be finished in two to five years. Those included everything from a floating pool, to an outdoor market, to a science center.

“Our priorities in the short term is to really both bring new green space along the riverfront and then to bring activities to the north and south of RFK,” said Jason Long with design firm Oma.

The plans all feature additional green space, pedestrian walkways and bridges plus access to the river.

Events DC, the city’s official convention and sports authority, presented the concepts after a series of public meetings.

Attendees at Monday’s event gave feedback, and Events DC will continue to gather more.

No projected cost estimates have been released, but they are expected in the next three months.