astroengine writes "With the help of rover Curiosity, we now know that ancient Mars had large quantities of liquid water flowing across its surface. However, evidence for large bodies of water — i.e. seas/oceans — has been hard to come by. But using high-resolution orbital data, Caltech scientists now think they've found a long-dry river delta that once flowed into a very large body of water. Welcome to the Aeolis Riviera — the strongest evidence yet for a Martian coastline. "This is probably one of the most convincing pieces of evidence of a delta in an unconfined region — and a delta points to the existence of a large body of water in the northern hemisphere of Mars," said Roman DiBiase, Caltech postdoctoral scholar and lead author of the paper that was published (abstract) in the Journal of Geophysical Research."