The rise of kink-unstable magnetic flux tubes through the solar convection zone is discussed with a view to explaining the subsurface origin of active regions. In spite of the advances and insights obtained by analytical and numerical means in the past decade(s), there are still important uncertainties as to the viability of a mechanism of this kind to explain the origin of sunspots and active regions. In this paper, the main features of the rise of kink unstable tubes and some open questions regarding this process are presented.