Readers will delight in exploring the history and science behind Earth's spherical shape.

Does Earth look round to you? -- What were people's early ideas about Earth? -- Who first thought Earth may not be flat? -- How do stars prove Earth is a sphere? -- How can climbing prove Earth is a sphere? -- Does Earth's gravity prove it's a sphere? -- Why are Earth and the planets spherical? -- How is it 1 a.m. and 1 p.m. at the same time? -- Can geometry prove Earth is a sphere? -- Can shadows tell us about Earth's shape? -- Did sailors know Earth was round? -- Is Earth a perfect sphere? -- Galaxy quiz.