Dogs can die of bloat within several hours. Even with treatment, as many as 25-33% of dogs with GDV die. The gastric dilatation is one part of the condition and the volvulus or torsion is the second part. In bloat (dilatation), due to a number of different and sometimes unknown reasons, the stomach fills up with air and puts pressure on the other organs and diaphragm. The pressure on the diaphragm makes it difficult for the dog to breathe.
The tunnel systems were of great importance to the Viet Cong in their resistance to American forces, and played a major role in North Vietnam winning the war. The Cu Chi tunnels were built over a period of 25 years that began sometime in the late 1940s during the war against the French.
The Zhongnanshan tunnel passing through the Qinling mountains in Shaanxi province of China is currently the second longest road tunnel in the world. The 18.02km long tunnel is currently the world's longest twin-tube tunnel. It was opened in January 2007 after nearly five years of construction.