Mysterious Giant Landmarks

Something strange is going on in Asia, the world’s biggest landmass. Somebody has been making strange markings on the ground that can only be seen from a high altitude or space. These landmarks have been made in many locations over a period of at least fifty years. What’s going on?
See here for background: http://hpanwo-voice.blogspot.co.uk/2013/08/strange-pentagram-in-kazakhstan.html