VLT and Keck near-infrared images of Titan's surface and lower troposphere can be subtracted to reveal widespread cirrus-like clouds of frozen methane (lower images) and a large patch of liquid methane (dark area within box) interpreted as clouds and morning drizzle above the huge continent of Xanadu (outline). At left is a chart of Titan's aerosol haze versus altitude, indicating higher density haze over portions of the south pole and the heights of frozen and liquid methane clouds.