A friend posted a photo of her daughters examining something tiny in the road. Up ahead of them is an enormous chasm where the road has been destroyed and washed out. They're absorbed in something minuscule while ignoring the most obvious point of interest. What idiom would describe this?
If the insinuation is that they are purposefully ignoring the chasm:
the elephant in the room
"Elephant in the room" is an English metaphorical idiom for an obvious truth that is going unaddressed. The idiomatic expression also applies to an obvious problem or risk no one wants to discuss.
It is based on the idea/thought that an elephant in a room would be impossible to overlook. (source: Wikipedia)