How can we get from one place to another when something blocks our way? It might be a rushing river. Or it might be a huge cavern or a deep ravine. The answer to that question is to build a bridge. Learn about the different types of bridges, the civilizations and people who engineered and risked their lives to construct them, and the advances in bridge building that have made them safe and effective ways to keep us moving! This title will allow students to plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.