These Alps are covered with beautiful forests, wich Venice, at the time of her power, turned to profit; intractable mountaineers live there, like the inhabitants of the Sette Communi. One of the characteristics of the Julian Alps is the number of grottoes and subterranean channels which they embrace. From the river Isonzo to the frontiers of Bosnia there are more than a thousand, and the natives of the country say that there are as many streams below the soil as there are over it. Channels of this kind, when not filled with water, afford an entry into the Sette Communi.