11
Earth's moon
The fifth largest moon in the solar system, Earth's moon is the only place beyond Earth where humans have set foot. The brightest and largest object in our night sky, the moon makes Earth a more livable planet by moderating our home planet's wobble on its axis, leading to a relatively stable climate. It also causes tides, creating a rhythm that has guided humans for thousands of years. The moon was likely formed after a Mars-sized body collided with Earth.
11