Bent pipes are ubiquitous in both man-made devices and biological systems, and are of great interest to both the industrial and the medical communities. The present talk gives an overview on different dynamics of the newtonian, incompressible flow inside toroidal and spatially developing ('elbow') pipes. The focus is on the mechanisms that lead the flow from a stable, steady-state trough instability and, ultimately, transition to turbulence. Special attention is paid to toroidal pipes, which allow to isolate the effect that the curvature has on the flow and the instability mechanisms. The methods employed range from linear (modal) stability analysis, to fully non-linear direct numerical simulations and non-linear adjoints.