The Energy Capital Of The World, and because it holds that title, Houston by definition is the most important city in the world. Why is this the case every industry is a combination of these things

  1. Produces energy for other industries to use to the benefit of man
  2. Processes that energy to a usable form for other things, incl farming
  3. Uses the energy produced by industries in class 1 and 2 for the benefit of man
  4. Is theft

Since the foundation of the modern world is cheap energy from Oil & Gas. The capital of that industry is by definition the most important city in the world. Energy is simply the ability to do work. Therefore he who controls energy, controls the world.