The Iran Pakistan India Gas pipeline project seems quite interesting also known as IPI or Peace Pipeline project. From what I read in Wikipedia, the pipeline was first proposed back in 1950s, through an article published by Military College of Engineering, Risalpur. The latest news is that China may also participate in this mega project. The details of this project are quite amazing. The length of the proposed pipeline is 2775 kilometers. The pipeline will carry 22 billion cubic metres (780 billion cubic feet) of natural gas per year. The diameter of the pipeline is ~ 56 inches. Looking forward to interesting insights & details from civil & structural engineers.