The Danish-Icelandic artist Olafur Eliasson has brought his participatory installation "The collectivity project" to New York's High Line, with the public encouraged to envision an imaginary cityscape out of white Lego blocks.

A selection of architecture firms with current or ongoing projects in the neighborhood were chosen to kick off the installation. BIG–Bjarke Ingles Group, David M. Schwarz Architects, Diller Scofidio + Renfro, James Corner Field Operations, OMA New York, Renzo Piano Building Workshop, Robert A.M. Stern Architects, Selldorf Architects, SHoP and Steven Holl Architects were all asked to build one "visionary" structure or construction for the opening of the project on May 29.

And now, let the entropy begin. Through September 30, the hands-on project is open to the public, and those initial buildings are being altered, mounds of Lego blocks collecting between them, as they become part of the collective architecture that will come out of the four-month installation.

"The collectivity project" has previously set up camp in public areas in Tirana, Albania (2005), Oslo, Norway (2006) and Copenhagen, Denmark (2008). At the High Line, an elevated outdoor walkway in Manhattan, it is part of a larger group exhibition called "Panorama," inspired by the site's urban views and natural setting.

Free weekly public programs and educational activities are now taking place, encouraging interaction with the project and covering topics including urbanism and architecture and geared toward kids, families, teens and adults.

"The collectivity project" is on view on the High Line at West 30th Street through September 30.