North America will today see the first total eclipse of the sun in almost 100 years.
Named the Great American Eclipse, the moon will pass between Earth and the sun for America's first coast-to-coast total solar eclipse since 1918
The eclipse shadow is travelling at just over 1,100 miles per hour - fighter jets will find it hard to keep up with shadow racing across the USA from West to East. The shadow is 70 miles wide and the biggest city to fall under its spell is Nashville, Tennessee at 7.28pm BST.
But even with this chance in lifetime event, the weather will play an important part in whether spectators will be able to see this visual spectacle.
The phenomenon will last roughly 40 minutes with the mid-point occurring at different times around the country (see below for times in BST).
NASA are producing a live video feed of the event via their website and facebook page - NASA AMERICAN ECLIPSE
WILL WE SEE IT IN THE NORTH WEST?
Unfortunately the UK is not in the best pathway. Less than 10% of the sun will be obscured by the moon bewteen 7.30-8.30pm on the 21st August.
Cloudy skies and a setting sun will make the (very) partial eclipse almost impossible to see across most parts of the region.
WHEN WILL IT HAPPEN AGAIN?
To say there's been such a wait since the last one, the next Eclipse for the USA is in 2024.
The next significant eclipse for the UK - which will be total across Iceland, theAtlantic Ocean and Spain and a very large partial eclipse across Britain (at around 96% in Cornwall falling to 91% in Aberdeen) - will be in 2026.