It's a spectacle that won't repeat for another century - the sight of Venus slowly inching across the face of the sun.
So unless scientists discover the fountain of youth, none of us alive today will likely ever witness this celestial phenomenon again, dubbed a "transit of Venus."
It's so unique that museums and schools around the globe are hosting Venus viewing festivities - all for a chance to see our star sport a fleeting beauty mark. Even astronauts aboard the International Space Station plan to observe the event.