Construction on the world’s largest subterranean rail station is underway in China. When finished, the station will cover approximately 5 million square feet and have three levels for people to travel through. It is intended to connect Beijing and Hong Kong, two of China’s most populous cities, and will serve as a significant hub for high-speed rail travel throughout the country.The station is being built in an unusual way that involves pre-casting concrete segments and then assembling them on-site. This process is considered to be more efficient and produces a better product. The station is scheduled to open in 2025.When completed, the station will be a technological wonder and a testimony to China’s expanding economic and political strength. It will also play an important role in the country’s world-class high-speed rail network.