NASA has plans for a Cloud City on Venus, seriously.
Our nearest neighbor, Venus, is always ignored when it comes to explorations, probably because the surface is around 465C (870F). Venus is very similar to Earth otherwise, though, and is called Earth’s twin. It’s nearly identical in size and composition and gravity, we just can’t get anywhere near the surface. Even to send a robot would be difficult since the temperatures there are hot enough to melt lead.
But the atmosphere, however, is another questions.
The High Altitude Venus Operational Concept, or HAVOC (nice) is NASA’s plan which would first send a robot to test the atmosphere, followed by an crewed orbital mission, then finally a thirty day manned mission into the atmosphere of Venus, staying in solar-powered airships held up by helium. Yeah, it sounds like a sci fi movie. But NASA is actually seriously thinking about this.
Imagine, a cloud city on Venus full of scientists studying the planet below. The vision in my head is something like the scene below:
But… maybe I shouldn’t get my hopes up…
Jonas David 
Definitely a good concept but when the NASA doesn’t even have it’s own orbital rocket and we have to hitch a ride with the Russians or ESA it will no doubt remain the stuff of SF lore.