We conducted several experiments to determine the characteristics of an optimal wayfinding aid for new users of a complex building. In Experiment 1 wayfinders who used signs found their destinations fastest. Those using you-are-here maps were much slower than even those wayfinders given no aids. The main advantage of signs over you-are-here maps results from information-processing differences: Signs provide clear cues about turns and decisions without requiring study time or imposing a high memory load. In Experiment 2 we found that people prefer routes that require the least amount of energy expenditure. Contrary to findings of previous research, we did not find complexity to be an important variable. A third experiment, using artificial floor plans of buildings, confirmed that minimizing energy is much more important than complexity in determining preferred routes. Finally, in Experiment 4, we investigated wayfinders' heuristics and the information necessary to provide unambiguous signs.