Shamrock, Texas, travel stop;  picture postcard view is circa 1968.  Shamrock is the crossroads of the US, or at least one of the crossroads, as the intersection of US Route 66 and US Route 83.  While 66 famously ran from Chicago to Los Angeles, Route 83 runs from the US-Mexico border up to the Canadian border in North Dakota before proceeding further well north into Canadian territory.