Video screenshot by Tim Hornyak/CNET

For centuries, the people of Tokyo have been flocking to the Sumida River to see fireworks displays. This past weekend, though, they got a spectacle of a different sort as thousands of electric "fireflies" wafted downstream.

The Tokyo Hotaru Festival 2012 is a modern twist on the age-old Japanese love of watching fireflies along waterways. Some 100,000 blue LED light bulbs floated down the Sumida in imitation of the insects, long celebrated in haiku and other verse.

Measuring just over 3 inches across, the LED bulbs were charged with solar-generated electricity and later reclaimed in nets downstream.

Plied by yakatabune pleasure boats and commercial craft, the Sumida runs through the eastern half of central Tokyo and empties into Tokyo Bay.

The LEDs floated by the Tokyo Sky Tree, the world's tallest tower, which opens this month as a digital broadcast center and sightseeing attraction.

The tower was brilliantly flooded in blue-white lights for the event, which was accompanied by live music.

An added treat was the presence of the waning super perigee moon, which drew photographers around the world over the weekend.

You can see it rising by the Tokyo Sky Tree in the time-lapse video below.

(Via Kyodo News)