The second most recent transit of Venus observed from Earth took place on 8 June 2004. The event received significant attention, since it was the first Venus transit after the invention of broadcast media. No human alive at the time had witnessed a previous Venus transit since that transit occurred on 6 December 1882 in the 19th century.

European Southern Observatory (ESO) and the European Association for Astronomy Education (EAAE) launched the VT-2004 project, together with the Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE) and the Observatoire de Paris in France, as well as the Astronomical Institute of the Academy of Sciences of the Czech Republic. This project had 2,763 participants all over the world, including nearly 1,000 school classes. The participants made a measurement of the astronomical unit (AU) of 149 608 708 km ± 11 835 km which had only a 0.007% difference to the accepted value.