Fix $m,n\in\mathbb{N}$ with $m\ge n+1$. Take $m$ points in general position in $\mathbb{R}^n$ and let $P$ be their convex hull. What is the maximal number of (external, codimension-one) faces that $P$ can have, in terms of $m$ and $n$? (Apologies if this is a well-known quantity.)