Geology
Rila is a dome-shaped horst mountain, part of the Balkans' oldest land, the Macedono-Thracian Massif. It was formed by granite and gneiss rocks and crystal schists during the Paleozoic (250,000,000 years ago). Rila's alpine relief was formed during the Pleistocene by a series of glacial periods. During the most recent, so-called Würm glaciation, 10-12,000 years ago the permanent snow line was at 2,100 m above sea level. Above this line glaciers radically changed the existing relief, carving out deep cirques, sharp pyramid-shaped peaks, rock pinnacles, various valleys, moraines and other typical glacial formations.
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