If you ever ran into the "Weird Path Twist" (a.k.a Z-Twist or curve singularity twist) in Blender, I've opened a bug against it: [#8022] Some operations on control points can introduce weird twists in paths
If you don't know Blender, here is what I did in two days:
It's the entrance to a public bath on the TAURUS. Since the corridor outside is perpendicular to the bath's ground, it's a gravity lock; in the center of the circular walkway, you can see the floor make a 90° turn downwards to align visitors with the gravity field of the bath. If you want to gaze, you can stay on the circular walkway and have a great view of the bath without craning your neck.