As seen from Earth, only transits of the inner planets Mercury and Venus are possible. Planetary transits are far more rare than eclipses of the Sun by the Moon. On average, there are 13 transits of Mercury each century. Nowadays, all transits of Mercury fall within several days of May 8 and November 10. During November transits, Mercury is near perihelion and exhibits a disk only 10 arc-seconds in diameter. By comparison, the planet is near aphelion during May transits and appears 12 arc-seconds across. However be aware that the planet Mercury is too small to be seen with the naked eye in front of the Sun. It’s therefore essential to magnify the image using a telescope or any appropriate device to detect the black ball pinned in the foreground of the photosphere of our star.
On the 2006 Transit of Mercury visibility map you can see that the transit wasn’t visible from Europe. This is why I observed from Los Angeles in the western United States of America. In about five hours time the planet crossed the solar disk from east to west. It was the first transit of Mercury since 2003 and was visible from eastern Asia, Australia, New Zealand, Hawaii, the Pacific and the Americas.