Tales of Wuxia
Dragon Lines, also known as ley lines, are natural lines of life energy that cover the world. Only those highly attuned to these natural flows of energy can sense them, or make use of them. Strong individuals can even travel along them as if they were flying or make use of the vast chi/ki of a line to do any number of effects. However those who are not strong enough and try to make use of Dragon Lines run the risk of serious harm to themselves.
Youxia, who are strong enough, often use them to travel from one place to another. However the points where one can get on or off a Dragon Line are fixed and may not be the most convenient locations to where one wants to go. Even so, riding a Dragon Line can make a trip that on foot would take all day, take mere minutes. The desire for powerful men to allow transporting more than just a single person on a Dragon Line and one who is not talented is the entire reason Airships were developed.
The more mystical uses of Dragon Lines are rare to see in action. Mostly because the raw power resists manipulation forcefully. Dragon Lines can be thought of like rivers of Chi/Ki and only the most tame flows can be dealt with without considerable effort. The Rénmín in particular have placed physical objects, usually made of jade, over locations of Dragon Line Nexuses as a means of harnessing small amounts of the energy they contain.