We show on general theoretical grounds that the two ends of single-stranded (ss)\ RNA molecules (consisting of roughly equal proportions of A, C, G and U) are necessarily\ close together, largely independent of their length and sequence. This is demonstrated to be\ a direct consequence of two generic properties of the equilibrium secondary structures,\ namely that the average proportion of bases in pairs is\~{} 60\% and that the average duplex\ length is\~{} 4. Based on mfold and Vienna computations on large numbers of ssRNAs of\ **...**