The Benin Moat, also known as the Benin Iya, Walls of Benin or locally as Iyanuwo, are a series of massive earthworks encircling Benin City in Nigeria's Edo State. These moats have deep historical roots, with evidence suggesting their existence before the establishment of the Oba monarchy. Construction began around 800 AD and continued until 1460 AD, involving large-scale manual labour and the repurposing of earth from the inner ditch to build the outer berm. Some traditional sources claim that these earthworks spanned approximately , enclosing about of land.
The Benin Moat served as defensive structures, with steep banks and a berm to deter invaders. Access to the city was controlled through nine gates. Today, remnants of the moats can still be found in Benin City, although urbanisation and land disputes pose challenges to their preservation. Recognised for their historical significance, the Benin Moat was added as an extension to the existing World Heritage Site of the Royal Palaces of Abomey in 1995 (though still awaiting official recognition by UNESCO), and was acknowledged by the Guinness Book of World Records in 1974 as one of the world's largest man-made structures by length, second only to China's Great Wall. It was described by Olfert Dapper in his book Description of Africa in 1668 as the Great Walls of Benin.
History
Background
The origins of the Benin Moats, also known as the Walls of Benin, cannot be attributed to a single ruler or era. While Oba Oguola played a role in expanding and deepening the moats, evidence suggests that these moats existed before his reign and even before the establishment of the Oba monarchy. Various villages and wards that later coalesced into Benin City may have initially dug their moats for both defensive and boundary purposes. The moat is an example of large-scale engineering characteristic of the Benin Empire. It consisted of a combination of ramparts and intricate moats that encircled the city of Benin City in present-day Edo State, Nigeria.
Construction
The earliest phase of moat construction in the Benin Kingdom likely predates the Ogiso kings. Archaeological findings and oral traditions suggest that some moats were in existence before the arrival of the Ogiso rulers. These early moats served various purposes, including socio-political organisation, economic activities, and defense.
During the rule of the Ogiso kings, the culture of moat construction continued and likely expanded. Moats varied in their origins and purposes. Different villages and wards within the Benin Kingdom had their moats, often constructed for distinct reasons. The Ogiso kings contributed to the development of some of these moats, maintaining control and organisation within the kingdom. With the transition from the Ogiso kings to the Obas, the moat-building tradition persisted. Obas like Oba Oguola and Oba Ewuare re-dug and deepened some of these structures. The moats associated with the Benin Kingdom today, particularly the inner moat crossed during Obas' coronation, might have been deepened during Oba Ewuare's reign in 1440 AD. Oba Oguola, who reigned around 1280 AD, also played a role in moat construction.
Construction of the Benin Moat itself began as early as 800 AD and continued until around 1460 AD. This defensive system comprised inner moats and walls protecting Benin City, while outer walls extended to encompass numerous villages and communities. In total, the moat system spanned about and enclosed approximately of land. Manual labour was the sole means of construction, precluding the use of modern earth-moving equipment or technology. Earth excavated to create the inner moat was repurposed to build the external ramparts (outer walls). These walls varied in size, from shallow traces to towering structures reaching up to in height. The length of the Benin Moat ranks it among the most extensive earthworks in history.