PITTSBURGH (WPXI) — The cold did not stop people from flocking by the thousands to downtown Pittsburgh for Saturday’s Light Up Night. People and animals of all ages were there to enjoy the vendors, lights and more. The Highmark tree at Stanwix Street and Penn Avenue was lit. It’s a tradition going back decades. It was one of two trees lit Saturday. The Christmas tree outside the City-County Building was turned on just an hour earlier. The evening ended with a concert from rock legend Joan Jett and a 9:30 p.m. fireworks show. The holiday market at Market Square will be open through Dec. 23.