The United States and Japan are developing research submersible systems that will be able to explore the ocean floor's deepest spot: the 10,920-m Challenger Deep at the southern end of the Marianas Trench off the Mariana Islands. Sketch of the Shinkai 6500, a
Construction Time of the the Ming Wall. The Great Wall at Badaling. Over 2,000 years, many imperial dynasties and kingdoms built, rebuilt, and extended walls many times that subsequently eroded. The latest imperial construction was performed by the Ming Dynasty (1368â1644), and the length was then over 6,000 kilometers (3,700 miles).
However, if including all the walls built in different dynasties around China, the total length will exceed 50,000 kilometres.(The precise total length of Great Wall confirmed by the latest research work in 2012 is 21,196.18 km.) The Great Wall is not just a wall.