Help with school presentation?

For school, I have to give a presentation of what I think is beautiful. Not in a person kind of beautiful. Like what I think is beautiful and I have to give either a definition or a power point slide show but I don't know what to do! I don't really know how to describe beautiful if I do a definition and I don't know what to do in a slide show. I know what I think is beautiful like (sunsets, flowers, lanscapes, waterfalls) and different things like that but I don't why I think their beautiful. yeah cause the color is pretty and stuff but I need something very specific! Please help?! Thank yew! :D