and room-temperature lasing throughout the visible are demonstrated for ZnO nanocolumns grown on Au-coated tin-oxide glass. The directionality of the emission, the lasing threshold, and the observed mode spacing are all consistent with Fabry--Pérot lasing cavities. (P. O’Brien et al., September 3, Adv. Mater. 2002, 14, 1221-1224)