Tiangong-1, a Chinese satellite, is on final approach into earth but nobody knows where or when it will crash-land. China lost control of this satellite (actually a space station) for quite some time. Re-entry will be somewhere between the latitudes of 43N and 43S due to the inclination of its orbit but it is impossible to determine where and when the satellite will enter orbit (see chart below).
The satellite was launched unmanned aboard a Long March 2F/G rocket on 29 September 2011, it was the first operational component of the Tiangong program, which aims to place a larger, modular station into orbit by 2023.
Tiangong-1 is expected to land on earth tomorrow around 16:00 UTC. Depending on the density of the thermosphere which slows down satellites and debris to a speed that makes the orbital flight unsustainable, about 100km in the current conditions. At this time the satellite is located at 170km altitude (11:00 UTC).