Readers are asked to identify both hidden objects and twenty mistakes included in illustrations of ten famous explorations, from Marco Polo's journey to the East to Armstrong's journey to the moon. "Are you ready to become a history detective? Would Christopher Columbus have found Vikings in the West Indies? Did Neil Armstrong spot an alien on the moon? Test your knowledge of some of history's famous explorers by spotting 20 mistakes in every scene. Then turn the page and find out if you were right and learn more about ten amazing journeys of discovery!"--Page [4] of cover.