It's been an exciting few months over at Renzo Piano's office. No sooner has the practice finished celebrating the completion of their San Francisco California Academy of Sciences project than they are already getting ready for a second grand opening with the Art Institute of Chicago Modern Wing, scheduled to open in May.

See more images of the soon-to-be-completed Art Institute of Chicago extension

Considering that the Art Institute of Chicago holds the third largest art collection in the USA, it was hardly surprising when the need for more space became imperative. It wasn’t however till 2005 that work on the extension by the Italian Pritzker Prize winning architect finally began.

Light was central to the building’s design, as was sustainability. ‘There is always a bit of tension between providing light, and too much light. You want to see the art, but also protect it. We were in constant dialogue with the curators and the museum to fine-tune the interior lighting into perfection,’ RPBW partner Joost Moolhuijzen explains.

The wing’s green aspects are plenty, including recycling of the construction debris, a silver LEED certification, and a double exterior skin; this insulates the building, protecting people and the art from the harsh Chicago climate, but also making it more ecologically responsible. Additionally, the ‘flying carpet’ roof, as Piano likes to call it, features an innovative light filtration system with automated dimming, to take advantage of as much natural light as possible.

Not limited to the actual new wing - which includes large education spaces, galleries for the permanent collection of modern and contemporary art, as well as temporary shows, and a restaurant - the project also incorporates a detailed renovation of the Gunslaulus Hall. This existing gallery, spanning above the Illinois Central railroad tracks and hosting the Asian collection, links the old and the new parts of the building.

A 620-feet long steel bridge, known as the Nichols Bridgeway, connects directly the museum with the adjacent Millennium Park. The plan was for the two spaces to communicate and this happens through the bridge, but also through it’s light, transparent glass skin: ‘Not only can you see the park from the building, but you can also see the building’s interior from the park,’ adds Moolhuijzen. Furthermore, acknowledging Chicago’s strong architectural heritage, the new Wing was designed taking in consideration the rhythm of the neighbouring buildings’ façades and materials.

The Modern Wing will be in good company when it opens on May 16th. Piano recently completed a number of big cultural projects in America; the freshly opened California Academy, but also the LACMA in early 2008, and the Morgan Library and Museum

extension in NY, which won the Wallpaper* Best Public Building award in 2007.