North is to the top of each of the images.
The features seen on Europa's surface document both internal and external processes shaping the icy crust. Internal processes and the possible presence of liquid water beneath the ice are indicated by features such as 'dark spots', lobe- shaped flow features, 'puddles', 'mottled terrain', knobs, pits, and the darker areas along ridges and triple bands. Europa is subjected to constant tugging from the giant planet, Jupiter, as well as from its neighboring moons, Io and Ganymede. This causes 'tidal' forces that affect Europa's interior and surface. Evidence for such forces includes ridges, fractures, wedge- shaped bands, and areas of 'chaos'.