For each number field $F$, the picture displays the prime spectrum of the ring of integers $\mathcal{O}_F$ of $F$, visualized as a curve over $\operatorname{Spec} \mathbb{Z}$. This is by analogy with algebraic curves, since points on a curve over $\mathbb{C}$ are in bijection with prime ideals of its coordinate ring. Each prime ideal in $\operatorname{Spec} \mathcal{O}_F$ is drawn as a point, and the lines connecting the points are purely for aesthetical purposes, having no deeper meaning.
- A point is colored if it corresponds to a ramified prime, with ramification index corresponding to the hue of the point.
- The radius of a point is proportional to its residue degree.
In the portrait in the properties box, only the spectrum of $\mathcal{O}_F$ is drawn, while at the bottom of the number field page, we also draw $\operatorname{Spec} \mathbb{Z}$. This way we can intuitively study the fibers of the map $\operatorname{Spec} \mathcal{O}_F \to \operatorname{Spec} \mathbb{Z}$, where the fiber above a rational prime $p$ is the set of primes of $\mathcal{O}_F$ lying above $p$.