I am quite certain that there are pretty things in the world, but I have long struggled with figuring out if there is any sort of commonality among all the pretty things in the world. So I did an impromptu experiment by searching for beautiful things on Google images. This got me a very "Hallmark" collection, and leaves a number of things out. The overall impression I get is the Southern Living magazines my mother used to read.
Note that you can click on any of these pictures of a bigger version.
It seems like there could be a good, evolutionary reason for certain things to be pleasing to look at. People at the peak of reproductive fitness are pleasing to look at, and this makes intuitive sense. If a hallmark for human fertility were ooze dripping the forehead that smelled like rotten fish, you can bet your bottom dollar that there would be dead fish ooze art and dead fish ooze porn.
Food, similarly can be pretty, though it can also be really gross and that doesn't seem to correlate with taste or health. Pretty food is also sufficiently dissimilar to attractive people that I feel safe(-ish) assuming that attractive people are pretty for some underlying reason as opposed to thinking that attractive things are attractive because of similarities to attractive people.
Plants, especially colorful ones, are pretty. Flowers are the obvious examples, and return us to the notion of fertility as attractive, except that plant sex is a sufficiently niche fetish that I have trouble seeing it as driving cultural norms of beauty. Colors are often cited as a source of beauty, except that note the example below and the two women above are fairly white.
Maybe you can tie all these things together, but tell me about these things:
Perhaps I should admit that the secret of beauty eludes me .
We close today with a duet of William Shatner and Joe Jackson singing Common People over well-edited episodes of the animated Star Trek: