BBC NEWS | Science/Nature | Mars pictures reveal frozen sea:
"Mars pictures reveal frozen sea
The find has implications for life on Mars
A huge, frozen sea lies just below the surface of Mars, a team of European scientists has announced.
Their assessment is based on pictures of the planet's near-equatorial Elysium region that show plated and rutted features across an area 800 by 900km.
The team think a catastrophic event flooded the landscape five million years ago and then froze out."