27. Qin Shi Huang’s Tomb
Emperor Qin Shi Huang ruled China from 259 B.C. to 210 B.C. and is known for his elaborate tomb which was discovered accidentally by farmers in 1974. The tomb runs for miles in a vast cave system and is actually a palace built underground with a complete surrounding kingdom. There’s even a network of state-of-the-art drainage systems. However, no one has been able to breach the tomb to find what lies within. While surveys of the area know the palace contains high walls and other structures surrounding it, the depth of the palace and high levels of mercury have delayed any serious excavation. The Chinese government also worries that exposing the palace to air could destroy its preservation.