We visited recently for the annual firefly festival. When the sun goes down, all the walkways are lined with cut bamboo with little candles inside - a pretty sight. In the dark corners of the field there were fireflies and many people (who numbered more than the fireflies) crowded around looking at them.
I didn't come prepared for night pictures, so just took this one of the shrine building and another of a bamboo and candle arrangement.
Itsukushima Shrine was first built in 1807, and was originally a Benten shrine. Shine festivals are dedicated to the gods 市杵島姫神(イチキシマヒメ) and 倉稲魂命 (うがのみたま).