Baltic Shield (also Fennoscandia) is an ancient Precambrian shield in northern Europe, covering most of Sweden, all of Finland, the Kola Peninsula in Russia, and Karelia, plus the bedrock of the Baltic Sea. It mainly consists of exposed crystalline rocks formed during the Archean and Proterozoic eons (3100–900 Ma). Thus, it is by far the oldest rock in Europe! Over billions of years, the shield has been significantly leveled by erosion, and during the Quaternary (approximately the last 3 million years), it has been repeatedly scoured by continental glaciers, so the vast majority of its area now lies at elevations below 300 m. Nevertheless, it is not a completely flat landscape. In the northwest of Finland, at the junction with the Scandinavian Mountains, the highest peaks reach 700-800 m. And on the Kola Peninsula, the isolated Chibiny Mountains rise, with several peaks over a thousand meters. The highest is Judyčvumčorr (1200 m).