The seventh edition of Manifesta, which runs July 19-Nov. 2, 2008, is the Voltron of contemporary art biennials, comprised like that cartoon action hero of several units that combine to form one behemoth exhibition. By far the most ambitious in the series of European biennials put on by the Amsterdam-based International Manifesta Foundation (IMF), No. 7 ups the ante by embracing the entire region of Trentino/South Tyrol in northern Italy. It takes place in five major venues in four cities spanning some 80 miles. Indeed, visiting the show requires a real pilgrimage, though the half-hour train rides through northern Italian countryside from one venue to the next are certainly made less tedious by views of the Dolomites, its foothills striated by hillside vineyards.