I saw a meme the other day about how we are on a spaceship traveling at a mean velocity of 67,000 mph, spinning at 1,000 mph. In addition to that, the Sun circles the center of the galaxy at about 250 km/s, and the galaxy as a whole moves relative the "average velocity of the universe" at 600 km/s.
We don't know this, because can only measure speed relative to something else, but just thinking about it makes me dizzy!
Another dizzying notion is the sizes in the universe. This link leads to an cool website where you can zoom in and out to see sizes in relation to each other.