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"Boticas is known for vinho dos mortos (English: wine of the dead). During the invasion of the French army between 1807 and 1809 the inhabitants buried their locally produced wine in the sandy soil rather than let it fall into the hands of the enemy. After Napoleon's army, led by General Andoche Junot, was gone, they dug up the bottles.
Initially fearing that the wine had spoiled, the locals found the low temperatures and darkness seemed to concentrate the flavors and improve the taste. The practice of burying them for about two years it still routine and the wine is sold under the title of Vinho Regional Transmontano with the label of Armindo Sousa Pereira."
- Wikipedia