Detroit airport is a difficult airport. Concourse A is on one side. You go under ground to get to B & C. Concourse A is so long that it has a tram to take from one end to the other.
As you head under the tunnel, there is music playing to the lights illuminating from the side wall. It is a variety of methodical tempos. Different styles that are unique but blend together. All varieties that would be common at a spa. I figured that after designing a stressful airport, they added an area that everyone can pass through some relaxation and stress relief.