Skywatchers have been enjoying a rare event as Venus, appearing as a small dot, began passing directly between the sun and Earth.
Around the world people have been looking up at a sight which happens in pairs of eight years apart with more than a century between cycles. The next scheduled transit will be in 2117.
But it is not just a heavenly spectacle – collected data should help scientists in the search for habitable planets beyond Earth .
For amateur star gazers like one mother and son in the US it has been a chance not to be missed.
“It is a once in a lifetime opportunity to show him what goes on in the universe. We played hooky from school today to be here at 10 to try and teach him about the planets and what they do and the sun. It’s fun,” said Pavina de Silvaof from Los Angeles.
But beware, ordinary members of the public have been advised not to look directly at the sun without special eye protection.