The ice giants of the solar system have long been enigmas for science: Uranus and Neptune. Their beautiful blue-green colors hide under fat layers of thick atmosphere, where mysteries abound. But now, according to pioneering research, there seems to be a very exciting new theory-that both planets conceal huge oceans of water somewhere deep inside. Such an insight changes the idea of a much-expanded distant world entirely, about which it may seriously change the way we think about life beyond Earth.