Love the subjects!!!
A couple of things come to mind....taking into consideration that I'm a relative newbie to photography....
The images aren't very sharp, especially #5. (Some of the graininess is nice, but not in all cases) Also, while I love the arcitectual subjects, some of the photos are lacking something....shadows, details, focal points...? Also, be careful to watch that the photo is "straight", or that the subject doesn't look like it's falling backwards (#3). #2 is a great subject as well...but I think it would have been better to see the top of the arch?! :O)
I hope you find this helpful!!
;O)