A multiview postcard on Hissar or Hisarya (Хисаря). A popular resort town with its Roman relics. Thanks ceruleanmind.
It was sent together with three other postcards. A pair of 1,00лв figurine stamps and a 0,40лв moth stamp were used. The postmarks of Pleven are faint, only able to recognize "12 IX" for its date.