Vadim Erent runs Insight Cities, a tour company that promises to give visitors a deeper perspective on the cultural and political histories of more than half a dozen cities, including Berlin and New York. The firm began here in Prague, where the Russian-born US citizen has been living for the last 11 years. And our tour of “Vadim Erent’s Prague” begins near his Letná home, specifically on a bench overlooking Stromovka Park by the Místodržitelský letohrádek, or Governor’s Summer Palace.