Discovery of a 5,300-Year-Old 'Mysterious Giant Circular Structure' and 'Perimeter Wall'

Background and Objectives of the Research A research group led by Professor Ryoichi Kontani of Notre Dame Seishin University and Associate Professor Yuji Yamaguchi of Tokushima University, in collaboration with Professor Fikri Kulakoğlu of Ankara University, has been conducting archaeological excavations at the Kültepe site in Turkey since 2015 to explore the origins of cities in human history. This report presents the latest findings as of 2025.

Traditional Theories and Challenges in Urban Formation Traditionally, it has been established that the first cities in human history were born in Mesopotamia around 5,000 years ago, during the Late Chalcolithic period. This emergence is commonly attributed to the formation of stratified social structures driven by irrigation agriculture in the Tigris and Euphrates river basins. While recent theories have suggested the emergence of early cities in the rain-fed agricultural regions of northern Mesopotamia, these models remain fundamentally based on agriculture. However, the circumstances of urban birth in other West Asian regions remained largely unclear.

New Discoveries and Research Findings The research team hypothesized that urban societies might have been formed through the trade of rare resources, based on surveys around the Kültepe site. Excavations beginning in 2015 led to the identification in 2021 of a large-scale zigzag architectural site dating to around 3300 BC. In 2025, a portion of a perimeter wall exceeding 3 meters in depth was discovered to the east of this structure. The wall is circular, raising the strong possibility that this is a colossal structure reaching 100 meters in diameter.

Historical Significance This discovery is groundbreaking for three reasons: 1. It indicates that the emergence of cities in central Turkey may date back to the same period as the emergence of cities in Mesopotamia. 2. It suggests that the factors behind the birth of cities in human history were pluralistic, rather than solely based on agricultural models. 3. It represents the first time that such large-scale buildings or perimeter walls have been confirmed in central Turkey during this period.

Moving forward, the team will continue investigations to clarify the function of this perimeter wall (whether defensive or ceremonial) and to provide empirical evidence for urban formation mechanisms independent of agriculture.