TRAPPIST-1, a small red dwarf about 40 light-years away, has seven Earth-sized planets, announced in 2017. All of them orbit closer to their star than Mercury does to the Sun, taking 1.5 to 19 days. From one of them, its neighbours would sometimes look bigger than the Moon in our sky. Several lie in the zone where water could stay liquid.
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.