A Venus transit across the face of the sun is a relatively rare event — occurring in pairs with more than a century separating each pair. There have been all of 53 transits of Venus across the sun between 2000 B.C. and the last one in 2004. On Wednesday, June 6 (Tuesday, June 5 from the Western Hemisphere), Earth gets another shot at it — and the last for a good long while. But beyond this uniquely celestial oddity, why has Venus been an object worthy of ogling for hundreds of centuries?