On February 14, 1990, at astronomer Carl Sagan's request, Voyager 1 turned around and photographed Earth from about 6 billion kilometers away. Our planet shows up as a pale blue dot, smaller than a single pixel, caught in a ray of scattered sunlight. All of human history fits inside that speck.
A large share of Earth's water molecules formed in the interstellar cloud that existed before the Sun was even born, more than 4.6 billion years ago. You are literally drinking a cosmic fossil.
By day, the Martian sky looks butterscotch because of fine dust hanging in the air. But at dusk, those same grains scatter blue light forward, creating a bluish glow around the Sun. Rovers have photographed these blue sunsets: the exact reverse of what we see on Earth.