Liquid crystals are a unique medium for optical research. High optical anisotropy and the ease of its change in the process of reorientation induced by an electric field have resulted in great application significance. Equally interesting are properties related to optical nonlinearity, i.e. changes induced directly by a light beam. Two mechanisms of optical nonlinearity are particularly important: reorientation, in which the change in the orientation of the liquid crystal molecules, and consequently the local anisotropy of the medium, is induced by the electric field of the light wave, and thermal, where the change in temperature as a result of light absorption can lead to both a decrease and an increase in the refractive index. Both mechanisms, unique in optics, have been used to produce self-focusing light beams leading to the creation of optical spatial solitons, in nematic liquid crystals called nematicons. In addition to classical nematicons, a number of interesting results have also been obtained for vortex beams in recent years, including the achievement of vortex nematicons. This lecture will cover, in addition to a short introduction to nonlinear optics in liquid crystals, a number of examples of experimental observation of nematicons and vortex nematicons.