iPhone 5 Won't Display Horizontally—Why?

[mrlynn]

My wife was complaining that she couldn't turn her Calendar to show the horizontal grid. I checked, and nothing displays horizontally, not photos, nor Safari pages—nothin'.

I looked in Settings, but I don't see anything that would turn that feature on or off.

Something wrong with the phone?

EDIT: Power-cycling didn't help.

/Mr Lynn