A total solar eclipse - where the Moon fully blocks the Sun - will be seen across parts of North America on Monday.
It will begin over the Cook Islands in the Pacific Ocean, and then move across Mexico and 13 US states before finishing in Newfoundland and Labrador, Canada.
In the eclipse's path of deepest shadow - "totality" - the sky will go pitch black for four minutes and nine seconds.
You can watch live coverage throughout the day by clicking the play button at the top of this page.
This eclipse is rare as it will cover several densely populated cities, with some 31.5m people able to see it, Nasa says.
Nasa will conduct many experiments throughout the cosmic event, including launching rockets into the eclipse's shadow and sending research jet planes to track its path.
To enjoy the astronomical phenomenon safely, never look at the Sun with the naked eye, even with sunglasses on - wear solar eclipse glasses.
