It’s common knowledge that there could be no life as we know it on our planet without the presence of water. Its chemical properties make it the ideal solvent for myriads of biomolecules as well as the source of electrons in oxygenic photosynthesis. These are just a few of the many properties that render water essential for our kind of life. Evidence of extensive aqueous landscapes on our immediate planetary neighbors, Venus and Mars, shows that both planets had abundant water thousands of millions of years ago, probably in part thanks to heavy bombardment by water-bearing comets. However, even if life happened to begin on these planets, this water was lost due to various abiotic processes, whereupon any early life there became extinct. Mars and Venus settled into the extreme dryness that physics and chance have imposed on them. And yet, thanks to Gaia, our planet has successfully retained much of the water she received long ago contemporaneously with Venus and Mars.