Question

who is the maximum fort in the world history
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Answer 1

Answer:

Fort de Douaumant, or simply Fort Douaumont, was the highest and largest fort in a ring of 19 similar structures intended to protect the city of Verdun in France and was built in the 1890's. It consisted, primarily, of a network of underground tunnels levels protected with steel and reinforced concrete 12 meters thick

Explanation: