I went to a rock concert and into first part of show, i noticed a shimmering of lights off to the southwest of sky. i thought i was looking at the pleiades, as it was dark and the venue is up next to our wasatch mountains. it had the appearance of liquid in the sky that was bright and moving, i then realized i didn't know what i was looking at. it grew larger as it moved closer and slowly grew in height, flashing star like lights moving slowly in a long trail formation similar to birds, moving horizontally, no sound. a few reports were of 'orbs', 'fixed lights on very large object along with the flashing lights'. i saw only the flashing lights. they appeared to be as close as a flock of birds and looked similar to the flight formation birds would be in. the flash of the lights was large, making me believe it was close. also there seemed to be countless lights, i think hundreds. when the lights were over the entire venue, an unmarked helicopter appeared at the back of the venue with long bright headlights, it hovered for a few seconds before maneuvering around and disappearing. the lights had everyone's attention in my section of this outdoor concert, abt 3000 people attended. everyone in my area of west lawn were filming the sky, no longer watching the concert. the lights took at least 12 minutes, were over us for at least one entire song but i didn't time it. it seemed like forever that it moved above us. i thought the entire thing was beautiful and it seemed to coincide with the positive song that was playing, it was like looking at magic in the sky. it was amazing to see such a huge unknown band of lights cross through the night sky and everyone started to talk to the stranger next to them saying, maybe it was the stage lights reflecting off of something overhead, some people thought it could be part of the concert. i lost sight of the lights as it moved over the mountain to the north of the venue, heading northeast. i had a friend on the opposite side of the venue who didn't see the lights, only saw the helicopter and wondered what the heck it was doing so close to us. she said she had gone many times to the venue and had never seen a helicopter take that route, also she said it's lights were ext bright and unusual and that she was unable to tell what kind of helicopter it was. i saw the side of it and it had no markings except for red and white colors. my feeling afterwards was that i had had quite a remarkable experience seeing this unusual thing and i no longer really cared about the concert, it was all about seeing a ufo with so many other people. no one was upset or worried about the lights, quite the opposite. an article in one of the local papers said concert goers startled by lights in sky. i didn't see anyone startled. also no mention of the helicopter in the paper which came out a few days later, saying that it could have been glow sticks, lanterns or hot air balloons. to it's credit, the article did say that none of these possible explanations matched the description of what people had reported as seeing orbs. i think most people at show saw the lights but its hard to say exactly how many. i only counted the people around me that i can honestly say saw it.