Okay, I was a bit sloppy in my writing. What I meant was that almost always there is a reason for us liking it. For instance, we find other people sexually attractive BECAUSE our biology tells us to. We enjoy a fast car BECAUSE it gives us a thrill when we go at high speeds. With beauty, we can't (and this is quite Kantanian) say why something is beautiful, it simply is. — UngeGosh

You feel that things are beautiful also "because your biology tells you to." Something being beautiful is simply your brain being in a specific subset of states in response to that thing.

Beauty is part of the fabric of reality. So, beauty exists with or without human experience. What's my evidence for that statement? None, or rather, only experience. — Noble Dust

I disagree strongly with this. That something is beautiful is our reaction to it, and our reaction only. It's not a property of the thing in itself.

How is beauty connected to perception? — Noble Dust

It's a reaction often to things that we perceive.

Why did it take humanity so long to decide that this sort of music was beautiful? — Noble Dust

It seems like you answer your own question. Because that sort of music didn't exist yet. Why didn't it exist yet? Well music evolves gradually, and it took us a while to figure out how to make instruments and then to develop polyphony, counterpoint, the well-tempered tuning system etc.

So then there can't be any rights or wrongs when it comes to beauty? If beauty only is a reaction caused by our biology, then we can't have disussions with other people about what is beautiful?

What makes something beautiful is a bit of a mystery, but that beauty is in the eye of the beholder is not the right answer - that's just a related insight.

What makes something beautiful?

It all depends on what the things mean to the person and how the person looks at them at that moment.
Everyone has their own definition of beauty. What's beautiful in my eyes might not be beautiful in yours.
You don't know what the person has been through, you don't know what's on his/her mind.
For example,

(4)I see a beautiful flower and am entranced by its colors and shape. — River

not everyone likes flowers. They are cliche, some may say.

It all depends on what the things mean to the person and how the person looks at them at that moment.

This Romantic personal experience is always a factor, but it is not the only, or even the primary, factor.

Everyone has their own definition of beauty. What's beautiful in my eyes might not be beautiful in yours.

Morel like everyone has their own relation to the objective beauty of the material world as well as to the cultural ideology that mediates their relation to that objective beauty and to their objective body perceiving it and the ideology.

This Romantic personal experience is always a factor — Thanatos Sand

Personal experience isn't always romantic.

but it is not the only, or even the primary, factor. — Thanatos Sand

Well of course it's not the only factor. When you see something that you have never seen before, then there's no personal experience involved.

But it can be one of the primary factors. What something means to you can somehow link to your personal experiences. (Not in all cases, as I just explained, but most cases)
Let's say a lady, she got what every woman wants. When people see her, people will say she looks beautiful. But maybe something has happened between me and her in the past, and in my eyes, she's no longer beautiful.
Personal experience still somehow determines the beauty of something.

Yes, in your eyes she may no longer be beautiful, but that's an issue of your perception, not her beauty. So personal experience doesn't determine the beauty of an object, but the personal experience of it. Millions of Americans hated The Beatles when they came out, and nobody wanted to buy Van Goghs paintings when he was alive. Did that makes The Beatles and Van Gogh bad?