It's often said that the last thing you need to worry about when in a survival situation is what you're going to eat. The human body is highly resilient, and can go without food for longer than you think. On the other hand, shelter and water are pretty much non-negotiable in order to survive. However, it is possible to familiarize yourself with edible wild plants before you get into a survival situation, in which case you'll have a good idea of which wild plants you can eat if necessary. In addition, once you learn to identify some of these common edible wild plants, you might be able to add them to your diet while you're still in the city. Ever watched those shows where ordinary people are unexpectedly stranded in the wild and have to survive by their bare wits and living off nature? Notice how some poor guy always runs into trouble when he eats a plant he thinks is safe, but is actually highly poisonous? Clearly his survival instinct weren't up to part. Think you could do a better job? No matter where you are in the world knowing what plants are edible and which ones could kill you is a critical survival skill. You never know when you may be stranded in the woods, washed up on a deserted island, or have to fend for your self when the zombie apocalypse strikes (hey, it could happen).