More space to live
Space is a precious resource in a city. An underground system uses very little of it. A person driving a car at 40 km/h, however, needs an area of 60…
End of content
No more pages to load
space to live
Space is a precious resource in a city. An underground system uses very little of it. A person driving a car at 40 km/h, however, needs an area of 60…