Many organisms share the essential need to move through their environment to find resources, shelters, and mates as well as to escape predation. These movements are highly diverse across species, in terms of patterns and mechanisms, and are shaped by various ecological pressures. Despite this diversity, there are universal principles of navigation that apply across species and spatial scales. Integrating knowledge across organisms, this chapter provides an overarching framework underpinning the many ways species implement navigation across scales and goals. What common mechanism(s) could possibly unify the seemingly stochastic wandering of a unicellular organism, the foraging trip of a desert ant, and the more deterministic long-distance migration of vertebrates across land or ocean? Here, common principles are put forward that organize navigation across scales through different phases, transitioning from large-scale to fine-grained spatial resolution. Furthermore, a universal functional model of navigational systems is presented that operates at each of these scales. This model describes a set of modules functioning within a servomechanistic loop, whose completion underpins navigation at each phase. Enabled by species-specific sensorimotor systems and shaped by the navigational context, the model relies on a central integrator module. This integrator facilitates control of the motor system, which implements navigation behavior through decision making, planning, and continuous error correction. This model encourages a neuroethological approach to navigation, offering precise hypotheses to test at both behavioral and neuroscience levels.