The Art Institute of Chicago is set to open its new Modern Wing on May 16. Designed by Renzo Piano, the $300-million, limestone-and-glass structure adds 264,000 square feet to the existing 1893 beaux arts building, increasing gallery space by 35 percent and doubling education space. The wing debuts with an exhibition of 32 works from 2000-07 by Cy Twombly, on view through Sept. 13, and the installation of Charles Ray’s 38-foot-long sculpture Hinoki (2007), a Japanese cypress carved to look like a fallen tree, wormholes and all. Another feature of the new building is a 600-foot-long pedestrian bridge linking the museum to Millennium Park, which through October 2010 is featuring sculptures by four Chinese artists, a project of the city’s Department of Cultural Affairs. On view are stainless-steel “scholars’ rocks” by Zhan Wang, an oversize steel dinosaur based on cheap mass-produced toys by Sui Jianguo, camouflage-patterned oil pumps called “Kowtow Machines” by Shen Shaomin and a whimsical suspended cluster of gold-painted steel figures by Chen Wenling.