Frozen foggy lake and the castle of Trakai.
According to a legend after a successful hunting party, Grand Duke Gediminas discovered a beautiful lake-surrounded place not far from Kernavė, then capital of the Grand Duchy of Lithuania, and decided to build a castle in the location. That is how the Old Trakai Castle was built in Senieji Trakai. The name of Trakai was first mentioned in Teutonic Knights chronicles in 1337. This year is considered to be the official date of town's foundation.
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From @perfectsense