From 7.20, Sunday, till 13.24, Tuesday, Venus is making a unique passage through the solar disk. The phenomenon has not been witnessed for 122 years. Photo by Observatory of Valle d'Aosta, Italy.
The planet Venus is about to pass across the face of the Sun, a phenomenon that has not been witnessed in 122 years.
Europe, Asia and Africa offer the best view to the passage, and observers have been gathering there, getting ready for the rare sight.
There have only been six such transits in the telescopic age - in 1631, 1639, 1761, 1769, 1874 and 1882.
Venus will appear as a tiny black disc against our star. But people have been warned not to stare at it without the proper equipment, or they face the risk of blindness.