Koguryo was one of the Three Kingdoms of Korea, existing from 37 BCE to 668 CE. It was located in the northern part of the Korean Peninsula and parts of northeastern China. Koguryo was known for its military strength and cultural achievements, including the development of a unique writing system and impressive tomb murals. The kingdom played a significant role in the history of Korea, influencing the region's politics and culture. Koguryo's capital was Pyongyang, which became a center of power and trade. The kingdom eventually fell to a coalition of Silla and Tang Dynasty forces, marking the end of its influence.