Chernobyl, Ukraine, in 2009, satellite image. At the Chernobyl nuclear power station (upper left), on 26 April 1986, the nuclear reaction in Reactor number Four went out of control, leading to meltdown and an explosion. Radioactive fall-out contaminated the surrounding areas, with lighter elements carried large distances across Europe. A concrete sarcophagus, the Object Shelter, was built to contain the remaining radioactive materials. The large body of water (blue) is a 12 kilometre long cooling pond. Image obtained on 28th April 2009, by the Advanced Land Imager (ALI) on NASA?檚 Earth Observing-1 (EO-1) satellite.