How do the DNA components survive excitation by UV light? This question is of great importance to understand how the genetic code can be safely transmitted, or how the DNA components were selected by evolution. Computational chemistry has given some answers by elucidating the mechanisms of the main photoactivated processes involving the DNA nucleobases and their derivatives. IQCC researcher Lluís Blancafort is an expert in the field and has published a comprehensive review on the subject in Chemical Reviews, in collaboration with Roberto Improta from CNR Naples and Fabrizio Santoro from CNR Pisa. The review discusses how the excited species decay to the ground state, through conical intersections, the role of triplet states, the importance of charge transfer and excitonic states in larger systems, and the way the solvent and the environment modulate the photophysics. It finishes considering the current challenges in the field and future directions of research.