Sumida River Fireworks Festival (2015)

Japan's oldest recorded fireworks festival dates back to 1733, when it was staged as part of a ceremony to pray for victims of a severe famine the previous year. Today, it's by far the largest display in the capital – this year's will involve more than 20,000 fireworks – and regularly draws close to a million spectators. Note that the event will be postponed until Sunday if the weather is poor.