As me an two of my friends were going home at aprox. 23:35, i looked up at the sky and saw at a height of about 500m and at a distance of about 200m East a huge fireball flying from East to West at about 300Km/h. After 5-10 seconds the fireball stoped sudenly and i found it as an oportunity to take a picture but by the time i got my cell phone out of my pocket, it started accelerating and vanished in about 1-2 seconds following the same trajectory.I didn't see the acceleration myself because i was focused on taking a picture, but the guys i were with told me and they said that it got up to the speed of sound or past because we all heard a sonic boom.