system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Is there a reason that concert stages are raised above the audience but sport fields are lowered? Shouldn't they both be easily visible?

For example, the Coliseum floor (where the action is) is below all of the spectators so they can easily see what's happening, but almost all concert stages are raised above the audience. Is there a particular reason or is it just the way it is?
gpt
For sporting events, you want to be able to see the entire playing field, because the action might be anywhere on it.  The "bowl" design, with the field at the bottom, makes the most sense for this - everyone is above the action, and everyone can see any portion of the playing field.

For performances (music, theatre), you don't need to see the ENTIRE stage, just the front, where the action is happening.  Also, the performers can only face one direction at a time.  Consequently, the simplest design for a stage that the largest number of people can see is just constructing a raised platform.