This article introduces the topics in the "Connection Science" periodical's special March 2005 issue which focuses on navigation, which brings together scientists working on biological and artificial navigation. The first article deals with the problem of the degree to which animals rely on the geometry of the environment, rather than specific cues within it, to navigate. It also explains the use of motion information by agents that navigate. The role of optic flow in the issue of homing is investigated. Moving from insects and robots to birds, the next paper, by Wallraff, discusses the question of how homing pigeons home: a remarkable capability that has remained incompletely explained for many years.