The shape and history of the ellipse in Washington, D.C

When conic sections are introduced to mathematics classes, certain real-world examples are often cited. Favorites include lamp-shade shadows for hyperbolas, paths of baseballs for parabolas, and planetary orbits for ellipses. There is, however, another outstanding example of an ellipse. Known simply as the Ellipse, it is a gathering place for thousands of Americans every year, an