If anyone has seen the 'Life After People' documentary it would seem that if every living person simply vanished instantly that we would have not very much trauma in cities at all. Household electric appliances tend to be fairly trouble free and operate as they are intended to operate without human control, things like PCs and TVs and fridges and ovens just go on... and on... washing machines and dishwashers finish their cycles and go into standby. Such items as hot irons and possibly ride-on lawnmowers - and in a more spectacular sense cars, trains and aircraft would all crash or burn but I think the spectacular failures would be relatively minor.<br/><br/>Huge industrial plants are designed so they shut down without human inputs rather that fail catastrophically. Rules set by insurance companies and the environmental departments of governments ensure this.<br/><br/>Traditional coal- and oil- fired power plants are fuelled continually and manually by their operating staffs so within a few days all these sources of electricity would fail. Nuclear plants would run on, possibly for months it seems but these (quite obviously) are designed so that if human operation ceases they close down safely and don't go boom.<br/><br/>Yes there could be a small number of spectacular failures but 90% or more of the human world would simply fall silent, to be taken over by the animal and plant world in quite short order. In the documentary that's been mentioned, its postulated that in as little as 200 to 300 years whole cities would literally vanish and become little more than forests or forested 'hills'.<br/><br/>If you like your post-apocalyptia to have some edge of realism behind it, its worth a watch. Good for ideas and it contains many memorable images.<br/><br/>http://videosift.com/video/Life-After-People-full-documentary (http://videosift.com/video/Life-After-People-full-documentary)