More than 260 years have passed since the famous experiment on lightning carried out by Benjamin Franklin in 1752. Everybody knows that lightning is an electromagnetic phenomenon. However, scientific observation of lightning strikes and lightning currents is still of prime importance to achieve more complete lightning protection. Researchers in the Central Research Institute of Electric Power Industry (CRIEPI) and the University of Tokyo are observing lightning strikes and measuring lightning currents at Tokyo Skytree, one of the tallest freestanding towers in the world.