The name translates as the Old Mountains, aka the Balkan. This is the spine of Bulgaria, a desolate and dry area, yet dotted with fabulous waterfalls. Actually, it rained each day of our few days' hike there in the middle of an August and the last day we got soaking wet. On the first day, at the valley in the picture - we were heading up for Triglav Massif, its lower summits already showing up in this pic, and got lost for a while as the paths weren't marked - a weary backpacker nearly sat down on a nose-horned viper (Vipera ammodytes), coiled on the scree the path ran across.
Central
Stara Planina