My top ten, with photos:
Kitchener City Hall
Kitchener City Hall by Matt M S, on Flickr
The Walper Hotel
Lightning Over King and Queen by Matt M S, on Flickr
UW School Of Pharmacy
School Of Pharmacy by Matt M S, on Flickr
Kaufman
Kaufman by Matt M S, on Flickr
The Tannery
The Tannery by Matt M S, on Flickr
TD Centre
King and Ontario by Matt M S, on Flickr
Downtown Scotia Bank Branch
The Bank of Nova Scotia by Matt M S, on Flickr
Krug
Railway and Krug by Matt M S, on Flickr
Waterloo Life
Waterloo Life by Matt M S, on Flickr
Old Galt City Hall (Don't have a photo)
Some honourable mentions:
The York
305 King West
The Breithaupt Block
Kaufman Mansion (Ratz Bechtel)
Bullas Glass
Waterloo Region Museum
Old Kitchener Post Office
37 King Street West (Artisan Zone)
Rockway Clubhouse
KPL Central
Former Public Utilities Building
CIGI Campus
UW E5
Central Presbyterian Church
Old Galt Post Office
Kitchener City Hall
Kitchener City Hall by Matt M S, on FlickrThe Walper Hotel
Lightning Over King and Queen by Matt M S, on FlickrUW School Of Pharmacy
School Of Pharmacy by Matt M S, on FlickrKaufman
Kaufman by Matt M S, on FlickrThe Tannery
The Tannery by Matt M S, on FlickrTD Centre
King and Ontario by Matt M S, on FlickrDowntown Scotia Bank Branch
The Bank of Nova Scotia by Matt M S, on FlickrKrug
Railway and Krug by Matt M S, on FlickrWaterloo Life
Waterloo Life by Matt M S, on FlickrOld Galt City Hall (Don't have a photo)
Some honourable mentions:
The York
305 King West
The Breithaupt Block
Kaufman Mansion (Ratz Bechtel)
Bullas Glass
Waterloo Region Museum
Old Kitchener Post Office
37 King Street West (Artisan Zone)
Rockway Clubhouse
KPL Central
Former Public Utilities Building
CIGI Campus
UW E5
Central Presbyterian Church
Old Galt Post Office

