This is the story of a people's struggle for absolute security in a violent and dangerous world. Needing defense against the Mongols whose empire encompassed most of the known world, the Chinese built the Great Wall of China over 200 years. Thousands of miles long, the Wall was guarded by over a million soldiers manning thousands of forts and towers. Wonders of the World series The winner of numerous awards, this series is renowned for Elizabeth Mann's ability to convey adventure and excitement while revealing technical information in engaging and easily understood language. The illustrations are lavishly realistic and accurate in detail but do not ignore the human element. Outstanding in the genre, these books are sure to bring even the most indifferent young reader into the worlds of history, geography, and architecture. "One of the ten best non-fiction series for young readers." - Booklist