According the Guiness book of records (1974 edition) it described the walls of Benin city and its surrounding kingdom as the world largest earthworks carried out prior to the mechanical era. It was estimated that earliest construction began in 800 and continued into the mid-15th century. It enclosed 6,500 square kilometres (2,500 sq mi) of community lands. The combined length of the walls, was over 16,000 kilometres (9,900 miles).
Fred pearce wrote in New Scientist:
"They extend for soms 160 km in a mosaic of more than 500 interconnected settlement boundaries. They cover 2,510 sq. miles (6,500 square kilometees) and were dug by the Edo People. In all, they four longer than the Great Wall of China, and consumed a hundred times more material than the Great Pyramid of Choeps. They took an estimated 150 million hours of digging to construct, and are perphaps the larest single archaelogical phenomenon on planet."
Below are 8 Facts about The Great Walls of Benin (Summary)
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.