Here’s what you’ll learn when you read this story:Researchers discovered a secret sealed room in Ukraine’s historic Galician Castle. After accessing the sealed room, the researchers found that it was once a fortified space for storing weapons and testing artillery. For 300 years, nobody knew that a secret sealed room existed in Ukraine’s historic Galician Castle, let alone entered it. In the 14th century, Casimir III the Great led major renovations, after which the castle was used as a residence. Experts believe that the bombing of the castle buried the ventilation shaft, covering the recently rediscovered room.