We recall some classical results on the Hopf fibration $f:S^3 -> S^2$. We focus on the preimage of a curve gamma on $S^2$ via the projection $f$. It is known as the Hopf tube over gamma and we give some curvature properties. We point out, as application related to Physics, some developments on magnetic curves on the 3-dimensional sphere. We complete the lectures extending all these studies to the fibration $M^3(c) -> S^2(r)$, where $M^3(c)$ is an elliptic Sasakian space form.