century A.D. At the same time the production centers for pottery became highly centralized and vessels became standardized. Centralisation and elite control of production is demonstrated by the results of the archaeological excavations at Songok-dong and Mulcheon-ni in Gyeongju. These sites are part of what was an interconnected and sprawling ancient industrial complex on the northeast outskirts of the Silla capital. Songok-dong and Mulcheon-ri are an example of the large-scale of specialized factory-style production in the Three Kingdoms and Unified Silla Periods. The site was excavated in the late 1990s, and archaeologists found the remains of many production features such as pottery kilns, roof-tile kilns, charcoal kilns, as well as the remains of buildings and workshops associated with production. Capital cities, elite precincts, and monumental architecture Since the establishment of Goguryeo, its early history is well attested archaeologically: The first and second capital cities, Jolbon and Gungnae city, are located in and around today's Ji'an, Jilin. In 2004, the site was designated as a World Heritage Site by UNESCO. Since 1976, continuing archaeological excavations concentrated in the southeastern part of modern Gyeongju have revealed parts of the so-called Silla Wanggyeong (Silla royal capital). A number of excavations over the years have revealed temples such as Hwangnyongsa, Bunhwangsa, Heungryunsa, and 30 other sites. Signs of Baekje's capitals have also been excavated at the Mongchon Fortress and the Pungnap Fortress in Seoul. See also Heavenly Horse Tomb List of Korean monarchs Samguk Yusa References Further reading External links Three Kingdoms Period - World History Encyclopedia Korea's Three Kingdoms 50s BC establishments 57 BC 668 disestablishments Former kingdoms