RNA folds into intricate structures that enable its pivotal roles in biology, ranging from regulation of gene expression to ligand sensing and enzymatic functions. Therefore, elucidating RNA structure can provide profound insights into living systems. A recent marriage between in vivo RNA structure probing and next-generation sequencing (NGS) has revolutionized the RNA field by enabling transcriptome-wide structure determination in vivo, which has been applied to date to human cells, yeast cells, and Arabidopsis seedlings. Analysis of resultant in vivo ‘RNA structuromes' provides new and important information regarding myriad cellular processes, including control of translation, alternative splicing, alternative polyadenylation, energy-dependent unfolding of mRNA, and effects of proteins on RNA structure. An emerging view suggests potential links between RNA structure and stress and disease physiology across the tree of life. As we discuss here, these exciting findings open new frontiers into RNA biology, genome biology, and beyond.