Within the past years, cultural organizations have shown an increasing tendency to adopt technologically innovative solutions in their activities. This shift is attributed to the wider technological evolution, in general, and the manifold capabilities that modern mobile devices have, in particular. Augmented Reality (AR) applications constitute a typical example of an interactive solution which has been already applied in various domains (such as, recreation, education). Motivated by the wider adoption that this technological solution has received, this article discusses the design and the developmental steps followed to create an AR (marker-based) application, which is dedicated to the medieval castle of Arta in Greece. The application has been developed using the Unity 3D platform and the Vuforia Software Development Kit (SDK). As part of our ongoing research and development efforts, our future plans include the empirical evaluation of the developed application. In addition, we hope that the presentation of this work will motivate cultural organisation to consider the adoption and the use of the AR technology as a means to complement and enhance the visitors’ user and, consequently, learning experience.