"The image was captured on a summer evening in São José dos Campos [in São Paulo state] while a negatively charged lightning bolt was nearing the ground at 370 km per second. When it was a few dozen meters from ground level, lightning rods and tall objects on the tops of nearby buildings produced positive upward discharges, competing to connect to the downward strike. The final image prior to the connection was obtained 25 thousandths of a second before the lightning hit one of the buildings," Saba said.
He used a camera that takes 40,000 frames per second. When the video is played back in slow motion, it shows how lightning discharges behave and also how dangerous they can be if the protection system is not properly installed: Although there are more than 30 lightning rods in the vicinity, the strike connected not to them but to a smokestack on top of one of the buildings.