Crossing the Allegheny from Downtown, the golden “Three Sisters” suspension bridges – at 6th, 7th and 9th Streets – gesture toward the North Side. The  9th St. Bridge was recently re-named the Rachel Carson Bridge in honor of  the pioneering environmentalist; earlier, the 6th Street Bridge was renamed for Pittsburgh Pirates hero Roberto Clemente; during home games, the bridge is closed to car traffic and crowds saunter across. The Pirates’ stadium, the stunning PNC Park, is new as is Heinz Field for the Steelers’; they replace the 1960s-era Three Rivers Stadium. Also new are the freshly gridded streets and businesses around them, replacing vast parking lots. The next sister, at 7th Street, has been rechristened, too, for Pittsburgh native Andy Warhol, whose museum waits at the end of the bridge. Indeed, the North Side has even more museums than ballfields. From the Warhol, continue to installation-arts pioneer The Mattress Factory, as well as the National Aviary, the Carnegie Science Center, the Children’s Museum and the Museum of Photo Antiquities. Stop at the East Ohio Street shops, and wander the sculpture-strewn riverside trail from the stadiums to the 31st Street Bridge. Keep an eye on the Allegheny – and collect bonus points if you catch a kayak and a coal barge in the same frame.