This night event held at the Sumidagawa Riverside in Asakusa where people float paper lanterns to pray for peace.

Floating lanterns in Asakusa
浅草夏の夜まつり とうろう流し

Date: August 12th(Sat) 2017 6:30PM - 8:00PM
Venue: Sumidagaw Terrace on Sumidagawa Riverside, Taitoku, Tokyo

Information by Asakusa Tourism Federation (Asakusa Kankou Renmei)
http://e-asakusa.jp/en/event/3806

Getting there
1 min walk from Asakusa Subway Station