(1)I see a beautiful person and become attracted to them.
(2)I see a beautiful architectural structure and praise its form.
(3)I see a beautiful sky and revel in its hues and clouds.
(4)I see a beautiful flower and am entranced by its colors and shape. — River
Whenever I hear or see something or someone that is "beautiful", there are always other aspects of the object or person that come into play. For instance, a person who is "beautiful" might also be very sexual in ways which, taken alone or applied to someone else, would obscure physical beauty. Sexual appeal sometimes is not beautiful, it's on an altogether different wavelength.
A beautiful building needs to also be visually interesting. If it isn't interesting (in it's visual form) it probably won't be beautiful. The trouble with some modern, international style office buildings isn't that their forms, claddings, and settings are not attractive, they are just not very interesting. They are too smooth, too regular, too similar to other buildings of the same style.
Take these four buildings: Inland Steel in Chicago, Prudential in Boston, and the Seagrams and Lever buildings in New York -- all outstanding examples of their style:
Compare the Seagrams Building and Lever Building (New York). Both are definitely attractive (they were fairly early examples of their style), they are faithful to the urban, international style (maximization of usable space, minimal decoration, regularity of design, and so on. I like both of these.
Take the Prudential building in Boston. Privileged to stand alone out on a previously industrial/railroad site between Boylston and Huntingdon Avenues in the back bay, it had no visual or social competition for two or three decades. It's just a concrete box, and up close it is decidedly not beautiful--it's attractive only at a distance. It is probably even less lovely now, but I used to like the building, because I liked the area.
The Inland Steel Building in Chicago features very shiny stainless vertical elements and green-tinted glass. It's a striking building, day or night. I find it very interesting, but it's effect is corporate-cold, whether seen in January or July.
Is the Eiffel Tower beautiful? Billions have warm feelings toward it because it represents Paris, and it curves upward, rather than rises like a spike. It's structurally complex (ornate?). I haven't seen it first hand.
The thing is, whether it's music or buildings or poetry or people, is "beauty" one aspect of the whole, or is a summation of the whole? There are many pieces of music I love, but "beauty" isn't first in line. Sometimes it is power, or intricacy, or inspiration (as in, inspired instrumentation and melody, say). The Choral finish of Beethoven's 9th is beautiful, but as a summation of many aspects--melody, harmony, massing of voices, instrumentation, rhythm, text, etc.