Was at my daughters house in Crown Point celebrating 4th of July. Watching grandchildren doing some fireworks when we all observed a rather large black circle moving across the sky from the south moving eastward. There were 6 witnesses. The object looked like a smoke ring but too high up and never dissapated. Center almost look like it was jellylike, no color, see through (like an amebia) or like the way heat radiates from the top of a grill when hot. Watched it for several seconds and grabbed ipad trying to capture it on video which i did. Also took some still photos. Husband and daughter also took some snapshots of object. It continued to travel but as it got farther away we lost sight of it. At first we thought it was birds but just didn't look the way we had ever seen them migrate before and shape did not change. I suppose it could have been some kind of insect swarm except for that wavy like middle and the fact it never seemed to loose circular shape. I had a really funny feeling afterwards. Can't explain. Just felt like we witness something really strange.