Downtown Houston Post Office

Buffalo Bayou at the Downtown Post Office - Franklin St Bridge
(June 2014 photo)

United Stats Post Office on Franklin Street (Main Office in Downtown Houston)

Also endangered and reported to be facing demolition: U.S. Post Office Downtown

Preston Street Bridge with Post Office behind it

Uncle Sam apparently does not like pooches. 
Dogs Beware: You are not to come on U.S. Postal Property:

Dogs are banned from post office premises - Sign posted at Franklin St. Post Office