Today, I went to the Cheong-deok Palace. I will talk to you about In-jeong-jeon in Cheong-deok Palace. In-jeong-jeon is a place where king has ceremony. The ranking stone in the way of the In-jeong-jeon shows the person's level. People who have high level is closer to the king. The stone in the ground is called ¹Ú¼®. I think our ancestor's was very smart. ¹Ú¼® made me to think our ancestor's was very smart because it is rough to protect king from the sunlight and protect from falling down when it rains. So, I think that ¹Ú¼® was very good idea.