Those lights are actually bioluminescent shrimp, better known as sea fireflies, or, in Japan, as “umibotaru”. Visible every year from May until the end of October, they live in the sand around very shallow sea water and are often seen floating between the extremes of high and low tides. Here: Bioluminescent sea fireflies glittering like diamonds on the rocks and sand. Okayama, Japan. July 2016. (Photo by Trevor Williams/Jonathan Galione/Getty Images)