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).
The Great Wall is a series of stone and earthen fortifications in China, built, rebuilt, and maintained between the 5th century BC and the 16th century to protect the northern borders of the Chinese Empire during the rule of successive dynasties.alls were being built in order to protect the Chinese empire as early as the 7th century BC. However, the collection of walls which have become known as The Great Wall of China were mainly built from 220 to 206 BC.