[Scale: 220 x 475 miles. Smallest discernable feature: ~1 mile across.]

"Circular" Reasoning:

Near Europa's equator, an area the size of Nebraska contains large circular plates of ice that have been fractured, separated, twisted, and rotated. The easiest way for these types of motions to occur is if a layer of liquid water or warmer ice existed beneath these regions when the activity occurred. Conclusive evidence as to whether subsurface oceans, seas, or lakes exist today will require future missions with instruments capable of peering below the ice. Extended Caption