I will explore aspects of the Coulomb-branch physics of five-dimensional superconformal field theories (SCFT). More precisely, I will consider the 5d SCFT on a circle, and describe the general structure of the Coulomb-branch BPS states as encoded in a "5d BPS quiver," which can be computed from standard string-theory geometric-engineering techniques. The interplay between 4d and 5d BPS quivers will play a central role in our story.