The legacy of the Great Walls of Benin has largely been forgotten. However, it does not change the fact that the Walls of Benin City was the world’s largest man-made earth structure lengthwise, and was hailed as the largest earthwork in the world. African History: 8 Facts about The Great Walls of Benin The Walls of Benin were used as a defense of the historical Benin City, formerly of the now defunct Kingdom of Benin and now the capital of the present-day Edo State of Nigeria. It is considered the largest man-made structure lengthwise and was hailed as the largest earthwork in the world. It enclosed 6,500 km² of community lands. Its length was over 16,000 km of earth boundaries. It was estimated that earliest construction began in 800 AD and continued into the mid-1400s. The Benin Walls were ravaged by the British in 1897 during what has come to be called the Punitive expedition. Scattered pieces of the structure remain in Edo, with the vast majority of them being used by the locals for building purposes. What remains of the wall itself continues to be torn down for real estate developments. The Walls of Benin City was the world’s largest man-made earth structure. In all, they are four times longer than the Great Wall of China, and consumed a hundred times more material than the Great Pyramid of Cheops. They took an estimated 150 million hours of digging to construct, and are perhaps the largest single archaeological phenomenon on the planet. The Benin Empire was a pre-colonial empire located in what is now southern Nigeria. Its capital was Edo, now known as Benin City. The Benin Empire was one of the oldest and most highly developed states in the coastal hinterland of West Africa, dating perhaps to the eleventh century CE, until it was annexed by the British Empire in 1897.