Look directly above you. This imaginary point directly above you in the sky is called the zenith. Astronomers believe there is no zenith for the Sun's position, but to any observer, the Sun has reached its zenith if it's directly overhead. The zenith is the highest point on the celestial sphere and is furthest away from the gravitational pull. The opposite direction is called the nadir. On the International Space Station, zenith and nadir are used instead of up and down when referring to directions around the station relative to Earth. Mark your zenith with this dainty Art Deco inspired design.