The mechanisms involved in protein folding strongly affect the biological function of the molecule, as well as the arising of diseases. Thus, it is important to determine all the possible pathways followed by the protein in its transition from the native state to the denature one (and back), as well as the possible intermediate states between them. To this aim, we performed pulling and hopping experiments with optical tweezers, perturbing in a controlled way the native state of the protein with a mechanical stimulus, and monitoring in real time the response of the molecule. In this way, the free energy landscape of the molecule can be reconstructed.