Hyr­can­ian forests form a unique forest­ed mas­sif that stretch­es 850 km along the south­ern coast of the Caspi­an Sea. The his­to­ry of these broad-leaved forests dates back 25 to 50 mil­lion years, when they cov­ered most of this North­ern Tem­per­ate region. These ancient for­est areas retreat­ed dur­ing the Qua­ter­nary glacia­tions and then expand­ed again as the cli­mate became milder. Their floris­tic bio­di­ver­si­ty is remark­able: 44% of the vas­cu­lar plants known in Iran are found in the Hyr­can­ian region, which only cov­ers 7% of the coun­try. To date, 180 species of birds typ­i­cal of broad-leaved tem­per­ate forests and 58 mam­mal species have been record­ed, includ­ing the icon­ic Per­sian Leop­ard (Pan­thera par­dus tul­liana).