A pro-Russian separatist holds a stuffed toy found at the crash site of Malaysia Airlines flight MH17, near the settlement of Grabovo in the Donetsk region, on July 18. As international investigators head to rebel-held eastern Ukraine to piece together what - and who - caused the Malaysian airliner to plunge into the steppe, securing evidence in the middle of a war zone is a major challenge. Reuters/Maxim Zmeyev