From the NASA website:
 The surface of Europa, a moon of Jupiter, consists mostly of huge blocks of ice that have cracked and shifted about, suggesting that there may be an ocean of liquid water underneath.
An unusual moon...

*One of the smoothest bodies in the solar system
*None of the valleys, ridges, pits, blisters, or icy flows go above or below the surface any deeper than a few hundred yards. Though the ice crust is 2 miles deep.
* Europa has a hot core. Hotter than thee surface.  The gravitation pull of Jupiter and Jupiter's satellites pull the moon's interior  in different directions causing heat.  

And ... A bit of text about Europa's mythology (greek)
Europa is named after the beautiful Phoenician princess who, according to Greek mythology, Zeus saw gathering flowers and immediately fell in love with. Zeus transformed himself into a white bull and carried Europa away to the island of Crete. He then revealed his true identity and Europa became the first queen of Crete. By Zeus, she mothered Trojan war contemporaries Minos, Rhadamanthus, and Sarpedon. Zeus later re-created the shape of the white bull in the stars which is now known as the constellation Taurus.
And, Ganymede has it's own magnetic field.