20s. Three piece suits and awesome hats.
Ypou said "this century/ since 1900", Until I saw that detail, I was thinking to before Adam and Eve got kicked out of the Grden of Eden. As in before they ate the forbidded fruit. I don't have a clever or intelligent answer for the time period of 1900 through nowish. :(
I can't speak too well to fashion. I still have a thing for 70's hair styles, though, especially that fluffy kind Farrah Fawcett wore on Charlie's Angels.
80s!! I love big hair!!
The Art Nouveau period.
The sixties that was a time of make love not war, peace and tie dye.