This is something cool I learnt today!
So, you may have heard how the great wall of China is the only human structure visible from space. Or how that claim is actually bollocks and totally made up :)
In reality, the largest human-made structure visible from space is El Ejido, a large complex of plastic greenhouses in the province of Almería, southeastern Spain. The complex covers about 26 thousand hectares (100 square miles) in the province of Almería, Andalucía, Spain and is also known as the "Plastic sea" for obvious reasons.
The complex produces a significant portion of Europe’s fruits and vegetables
Photo via Nasa, public Domain
What's so interesting about El Jido is that the complex of white greenhouses covers so much area that it has resulted in a cooling effect of 0.3°C (0.5°F) per decade in Almería compared to a 0.5°C increase per decade in the surrounding region. These two numbers combined give us a buffering effect of -0.8°C.
This is due to the sunlight reflected thanks to the white color, a phenomenon known as albedo.
The case of El Jido has actually sparked discussions and research on how humans can use the albido as a viable option for adaptation global warming, especially in urban areas. Even something simple as painting buildings and rooftops white could have large effects.
Anyways, next time somebody tells you about the myth of the great wall of china blah blah...point them to El Jido!
Or this wiki article with other human made structures visible from space :)