What is a structure? -- What are some of the first structures? -- How do builders plan a structure? -- Can you see a structure before it is built? -- How do builders choose a structure's style? -- When should old buildings be protected? -- How are old buildings cleared to build new ones? -- What machines are used to build structures? -- How is land prepared for building? -- What is treated lumber? -- How are cement and concrete used? -- What are simple machines? -- How do cranes lift so much weight? -- How are skyscrapers built? -- How do skyscrapers withstand forces? -- What do elevators do? -- How are bridges built? -- How are dams built? -- Who is Frank Gehry? -- How do buildings keep people safe? -- Construction careers -- Young scientists at work -- Take a construction test.