The Rose Kennedy Greenway (617-292-0020, rosekennedygreenway.org) has certainly attracted a lot of attention since its official debut in 2008. This linear park system covering the area where the old Central Artery used to stand has increased its already prominent profile in recent years by hosting more and more temporary public art exhibits. The latest such display may have outdone them all, however, as it features the work of one of the most prominent artists in the world, Chinese provocateur Ai Weiwei. His Circle of Animals/Zodiac Heads consists of bronze busts depicting the 12 animals of the Chinese zodiac, which have been placed on 10-foot-high stands and situated around the popular Rings Fountain, in prime position to delight visitors throughout the summer and into the fall before the exhibit closes in October.