The sight of a power plant belching out smoke is not usually regarded as one of the most beautiful in technology.
But when that power plant is BIG's Amager Bakke Waste-to-Energy Plant, and the smoke in question is actually water vapour in the form of a perfect ring, it's a little different.
The smoke ring system is part of a design to replace a 40-year-old power plant with a waste-to-energy plant, along with a ski slope.
The ring would blast out through a 124-metre chimney each time 250 kilograms of carbon dioxide is released into the atmosphere, in an effort to remind residents of their carbon footprint.
Dezeen has more details about the idea and how it works here.