The phrase "to be on cloud nine", meaning that one was blissfully happy, started life in the United States and has been widely known there since the 1950s; it’s since spread worldwide. It’s said to have been popularized by the Johnny Dollar radio show of that period, in which every time the hero was knocked unconscious he was transported to Cloud Nine. But that wasn’t the origin of the phrase. It’s been around since the 1930s, though early examples show a lot of numerical variability, with the cloud sometimes being as low as number seven or eight or as high as thirty-nine, though seven and nine were most common. These discrepancies make me suspect the usual explanation of its origin, which is that it comes from the US Weather Bureau. The story is that this organization describes (or once described) clouds by an arithmetic sequence. Level Nine was the very highest cumulonimbus, which can reach 30,000 or 40,000 feet and appear as glorious white mountains in the sky. So if you were on cloud nine you should be at the very peak of existence.
Delicate Arch, arguably the main attraction of Arches National Park is viewed from a side angle across the canyon. There are a few people around and below it, so you can see the sheer size of its formation (65-ft/20 m tall freestanding). Behind it, a massive summer storm is moving in, on cloud nine... Thank you all for your support and feedback!