From the Surface of the Castelo Branco Plain rise extraordinary the Inselberg granites of Monsanto-Moreirinha-Alegrios, like an archipelago of granite. These geological formations, hills which abruptly emerge from the surface, stand out like "island-hills." The origin of these is in the magma embedded in the Earth´s interior, which approximately 310 million years ago was exposed due to tectonic rising processes and climatic changes, and the removal of the weathered covering. In parallel the intense erosion sculpted these varied geoforms, including the unorganised chaos of blocks, polygonal fissures, sinks, tafoni or pillared blocks. The abundance and diversity of granite blocks characterised the connection between the population and the stone, thus associating the stone giants with local mythology and using them in everyday life, as a resource. This geomonument is one of the ex-libris of the Naturtejo Geopark. It is possible to see the entire Inselberg from any surrounding point, especially from the Idanha-a-Velha - Carroqueiro road, from where a panoramic view of the imposing geological feature can be observed. In Monsanto, in the Baluarte Lookout Point, and at the geodesic vertex of the castle, some aspects of granite morphologies, the Moeirinha and Alegrios Inselbergs, as well as the surrounding landscape, can be observed. In order to comprehend the complete dynamics of granite alteration and the formation of the geological reliefs, the recommendation is to follow the Barroque Route which runs along the Monsanto Inselberg from the base to the top, through trails up the middle, and underneath the granite blocks.