“The world is an oyster” is a proverb that fist appears in a Shakespear’s play “The Merry Wives of Windsor”, and its meaning has changed to mean the world is ours to enjoy. We can travel wherever we want around the globe and accumulate experiences that will make us grow as human beings. But that’s not quite true, because there are many places on Earth that are difficult to almost impossible to reach. Aside from natural sites, among them are many man-made objects, such as underground shelters, underground and surface bases and private depositories. Here is a video of some of the most heavily guarded places on earth that only a few are able to access. For the rest of us we can only speculate as to why we aren’t allowed to visit.