Как по Английски будет видимая часть айсберга

phrase

The small perceptible part of a much larger situation or problem that remains hidden.

Примеры использования:

The plastic that can be seen and cleaned from the shore is just the tip of the iceberg

idiom

A small and known part of something much larger and unknown

Примеры использования:

As with many injuries, the damage we can see is only the tip of the iceberg.