Radar images of a hydrocarbon sea on Titan taken by NASA's Cassini spacecraft. They show the evolution of a transient feature in the large hydrocarbon sea named Ligeia Mare on Saturn's moon Titan. The images at left show the same region of Ligeia Mare as seen by Cassini's radar during flybys in (from top to bottom) 2007, 2013, 2014 and 2015. The bright features are examples of active processes in Titan's lakes and seas. The changing nature demonstrates that Titan's seas are dynamic environments. The large panel shows Ligeia Mare, which is Titan's second-largest liquid hydrocarbon sea with has a total area of about 130,000 square kilometres. This panel is a mosaic of five synthetic aperture radar images acquired by Cassini between 2007 and 2014. It shows a region approximately 530 by 490 kilometers in area.