River Of Light With Electronic LED Fireflies, Sumida River, Tokyo

Behind the display, a hi-tech display lit up Tokyo's Sky Tree tower. The 100,000 LED lights were created by Panasonic specifically for the display. The lights are meant to represent fireflies - and highlight the connection between people and nature (with a little help from hi-tech electronics. The festival is a long-running Tokyo tradition - but this year Panasonic spiced it up with LED bulbs which automatically lit up on contact with water.