Seikan Tunnel, an undersea railway tunnel between the Japanese islands of Honshu and Hokkaido. With a length of 33.5 miles (53.9 km), it is the world's longest tunnel. It contains two tracks, allowing trains to run in both directions through the tunnel at the same time. Seikan Tunnel was completed in 1988 after 24 years of construction. It was bored largely through volcanic rock and reaches a depth of 790 feet (240 m) below sea level, some 325 feet (100 m) below the seabed of the Tsugaru Strait.
Central Asia, an indefinite region in the interior of Asia. It is generally considered to extend in a broad band from the Caspian Sea into the Xinjiang region of China, covering roughly the same area as Turkestan.
Tonle Sap, a lake in central Cambodia, drained by the Tonle Sap River. During the rainy season the lake receives water from many streams, mainly the flooding Mekong River, and greatly increases in size, inundating surrounding areas.