I looked it up and a size 11.5 womens in Australian sizing is a size 13 womens in the U.S. That's about 11 inches (28 cm). Somehow I don't think any woman on here will beat that... haha.
i take between a size 4 or 5 in UK sizes. well techically, my feet fit a size 4 length-ways, but my feet are very wide/broad and a size 4 is usually too narrow for me so i get a size 5 instead. i think it's 6 or 7 in US sizes i think? i'm 5 foot 6 so i'm a bit out of proportion i think (i think i'm supposed to have larger feet for my height really) - but i don't care.