Por-Bajin was discovered 1891 and is still a mystery for experts . The 3.5 hectare site is located in a Siberian lake near the Mongolian border . The unexplained site is estimated to have been built between 744-840 AD .
Por-Bajin was discovered a century ago and is still a mystery for experts . The 3.5 hectare site is located in a Siberian lake near the Mongolian border . The unexplained site is estimated to have been built between 744-840 AD .