Korea has a prodigious history in astronomy. Many astronomical books were published under Sejong the Great, and to our surprise, one of the books recorded that a concentrated alignment of Mercury, Venus, Mars, Jupiter, and Saturn was observed in BC 2467, almost 4500 years ago. Using an astronomical software, we confirmed that this alignment actually happened in BC 2470. The slight difference in time is considered negligible, as it is unclear what kind of calendar was used back then. During the speech, more examples will be given of the ancient observations of the sky, along with how many aspects of traditional Korean culture find their origins in the sky.