BETWEEN is a very interesting photo challenge.
Thank you, Broken Light Collective, for coming up with the theme.
Below, three takes:

The Tyrone Guthrie Centre at Annaghmakerrig: the hallway leading to the music studio on the top floor of the main house: Narrow Space Between Walls

Between Two Riverbanks: The Pedestrian Walkway Spanning the Thames Just Behind the Globe Theatre in London’s South End

Between Two People: Letter to a member of the Armed Forces serving in Iraq (Luke), showing what happens when it is almost 100% redacted (Letter was in a New Yorker short story)