First noticed a white light rapidly accelerating by and heading toward city skyline. object going much faster than a satellite and rapidly accelerating/decelerating unlike any plane. approached city skyline (southern side), then suddenly stopped moving and hovered in the sky. made several u-turn type changes of direction, and increased and decreased in brightness/light intensity as moved around skyline. it got pretty close to the sears tower for some if it's final moments and did more directional changes/hovers before descending in the se part of the sky near the lake and indiana/illinois border.