Today is a public holiday called 山の日(やまのひ, Mountain Day) in Japan. This is the newest public holiday which was established only in 2016.
For most people in Japan, today is the first day of “obon holidays.” “Obon” or “bon” is a Buddhism tradition observed in Japan. It is said that those who have passed away will come back on the 13th August to spend some time together with their loved ones on earth and they return to the other world on 16th. Most government offices and banks, and many businesses close for “obon” period, so many people can enjoy a 6-day break this year.
What they do to welcome the departed people differ from region to region, but one of the most famous “obon” events is 五山の送り火 (gozan no okuribi) in Kyoto (also known as 大文字 (daimonji)), which is observed in the evening of August 16th.
6 hills around the city of Kyoto have a letter （大 or 妙 or 法） or a symbol (a ship or a torii gate) carved on their side, which are visible throughout the year, and people in the neighbourhood pile up firewood in the shape of the letter/symbol and light them on the night of Aug 16 to make a bon fire to send those spirits off to the other world. The reason why it is called 五山 (five mountains) instead of 6 mountains is that 妙法 (myouhou – “marvelous law of Buddha”) counts as one. It is a very mysterious event. If you have a chance to be in Japan on the day, make sure you watch it on TV as many stations broadcast it live.