உலகிற்கே புதிராய் திகழும் ரஷ்யாவின் மர்ம கோட்டை பற்றி உங்களுக்கு தெரியும...

A Mysterious Fortress Has Puzzled The World! No man has been able to get the details of this mysterious fort that had been built centuries back. The walls of the fortress are well-preserved, while the walls inside are nothing less than rubble.