Древняя стена из железных блоков найдена в Сибири.

Why did the ancient Arabs, 11 centuries ago, call Siberia "the land of desolate cities" and say that caravans could travel along its ruined streets for 20 days? The Russian land from the Urals to the Pacific Ocean conceals thousands of mysteries. The chief among them is who the inhabitants of the ruined cities were, the remains of which are found here and there in the remote taiga and wild mountains. This structure is fantastic. The wall stood not only in a gorge 200 cubits wide (more than a hundred meters) but also rose up the mountain. The Arab describes the stones from which the wall was built as blocks one and a half cubits thick, iron and stuck together with rust. The wall reached 30 meters in height.