This stunning picture of the city of Bangkok, Thailand at nighttime was taken from the ISS by astronaut Reid Wiseman. Well, the concentrated bright white light was the city at least. The emerald green surrounding it? The astronaut had no idea. Was it nuclear waste? Glow in the dark algae? Alien sea monsters?
None of those, actually. NASA says that the glowing green light comes from the lights of countless fishing boats that make a living in the Gulf of Thailand. Yep, fishing boats.
The fisherman shine the light to attract plankton at night which in turn attracts the fish and squid that eat the plankton. The fisherman are then able to catch the fish and squid once they're closer to the surface.
It's a neat trick that leads to a beautiful picture.