Kendall Anderson's Daily pictures
Munsell Towers (WW2 aerial defence towers
Abandoned Japanese places (Japanese)
Gunkanjima deserted island (English/Japanese)
G-Cans! - Underground Flooding Fascility in Tokyo (Japanese)
Tokyo Geosite - Tunnel Infrastructure System underneath Tokyo (English/Japanese)
Restricted Industrial Area in Japan
Chinese urban environments by the photographer/artist Sze Tsung Leong
Urban exploration forum - loads of photographs of 'forbidden' places
Historical and New Buildings - Hi-res Building reference. (U.S.A)
NYC buildings - comprehensive list
NYC city photos - amature site with lots of proper ref material