I would love to see more differential geometry offered in undergrad. The course I envision would start with a review of vector calculus, move to studying hypersurfaces in $\mathbb{R}^n$, and then move into a study of manifolds. You could tie all these subjects together via the Fundamental Theorem of Curves, the Fundamental Theorem of Hypersurfaces, and the Fundamental Theorem of Riemannian Geometry. I feel such a course would help bridge the gap between undergrad and grad school; simultaneously reviewing the key ideas of calculus at a high level while also giving a solid foundation from which to study manifolds in grad school.

Here are some topics that could be covered:

• Curves in $\mathbb{R}^n$
• $k$-frames and curvature, leading to the Fundamental Theorem of Curves

• Hypersurfaces in $\mathbb{R}^n$

• Tangent spaces and curvature
• First/second fundamental forms
• Moving frames, Christoffel Symbols, Gauss Equations, Codazzi-Mainardi Equations.
• Fundamental Theorem of Hypersurfaces, a word on curvature tensors

• (Real) Manifolds, charts, multiple definitions of tangent vectors

• Mention Lie Bracket and Lie Algebras (after doing derivations for tangent vectors)
• Affine Connection, leading to the Fundamental Theorem of Riemannian Geometry

P.S. I am not a differential geometer. I study homotopy theory. I just thought a course like this was missing from the curriculum. Any feedback on other topics that could be covered or tangents that could be mentioned leading off from this material would be welcome.