13 historic monuments, puzzles which are still not solved

Dolmen Caucasus, Russia

On the slopes of the mountains are scattered small houses, built of flat stones. On the facade there is a hole, closed with a stopper. Surprising fact: the weight of the plates is calculated in tons, but they fit so precisely that between them can not squeeze and the knife blade. At this age artifacts reaches five thousands of years. Some monuments, such as Volkonskaya famous healing properties. Interestingly, the “dolmen tradition” can be seen in different parts of the Earth.