NASA website recaps 1859 Carrington Event the largest known solar flare observed by English astronomer Richard Carrington. "Just before dawn the next day, skies all over planet Earth erupted in red, green, and purple auroras so brilliant that newspapers could be read as easily as in daylight. Indeed, stunning auroras pulsated even at near tropical latitudes over Cuba, the Bahamas, Jamaica, El Salvador, and Hawaii." "Spark discharges shocked telegraph operators and set the telegraph paper on fire. Even when telegraphers disconnected the batteries powering the lines, aurora-induced electric currents in the wires still allowed messages to be transmitted." This entry on NASA website reassures "...statistics suggest that Carrington flares are once in a half-millennium events". Here is a link to an audio version of 1859 Carrington Event.