Houchengzui Stone City: This ancient Chinese megacity hides mysterious underground tunnels buried for over 4,000 years | World News
A huge ancient stone city buried for thousands of years in northern China has just become even more mysterious. Archaeologists working at the Houchengzui Stone City in Inner Mongolia have uncovered a hidden underground tunnel network dating back roughly 4,300 to 4,500 years. The tunnels were reportedly hidden beneath one of the largest and most…