Venus

Venus is the second planet in the Solar System. It was terraformed in the late 21st century.
Using floating islands covered in plants, which converted carbon dioxide to oxygen through photosynthesis, Venus had a breathable atmosphere. Venus did not have any natural seas, so most of its surface was a vast desert. The atmosphere of Venus had a high content of helium, which caused people to speak in a high-pitched voice, but was otherwise harmless. Pills could be taken orally to counteract the voice modulation.
Some of these plants had an adverse side-effect in humans called Venus Sickness. The airborne disease caused blindness in some people who came into contact with the spores. The Grey Ash plant cures Venus Sickness, but it is extremely rare and expensive to purchase. It is thus a valuable part of the black market trade on Venus.
The surface of Venus is very dry and characterized with flat plains, highland regions, and depressions. There are very few impact craters, in contrast with Mars, the Moon and Mercury. Civilization on Venus can be compared to 19th century Istanbul, Turkey 
Most people see signs using Arabic script that are are Farsi (Persian) and some of the stores have Turkish names (Gül market, Aile pazarı, Erdal, etc.). There are small nods to Persian and Turkish culture.