The total solar eclipse which starts in just over one and a half hours can be followed live through Nasa's online stream, filmed from the vantage point of 50 helium-filled balloons at a height of 24,384 meters.
Millions of Americans equipped with protective glasses have been taking positions along a ribbon of land cutting diagonally across the United States to marvel at the first total solar eclipse to unfold from coast to coast in nearly a century.
After weeks of anticipation, the sight of the moon's shadow passing directly in front of the sun, blotting out all but a halo-like solar corona, will draw one of the largest audiences in human history, experts say, when those watching via social and broadcast media are included.
Some 12 million people live in the 113-km-wide, 4,000-km-long zone where the total eclipse will appear today. Millions of others have travelled to spots along the route to bask in its full glory.
The phenomenon will first appear in the US at 10.15am PDT (7.15pm local time) near Depoe Bay, Oregon. Some 94 minutes later, totality will take its final bow near Charleston, South Carolina.
The last time such a spectacle unfolded from the Pacific to the Atlantic was in 1918. The last total eclipse seen anywhere in the United States took place in 1979.
The sun's disappearing act is just part of the show. As the black orb of the moon nibbles away at the sun's face in an eclipse, the heavens dim to a quasi-twilight and some stars and planets will be visible.
The next time people in Malta will be able to see an eclipse will be on June 21, 2020, when an annular eclipse will be visible, while the total eclipse in August 2027 will be visible from just to the south of Malta
Shadows on the ground seem to deepen, sunset-like colors streak the sky at the horizon, the air grows still, temperatures drop and birds cease to chirp as they settle in trees to roost.
The last glimmer of sun gives way to a momentary sparkle known as the "diamond ring" effect just before the sun slips completely behind the moon, leaving only the aura of its outer atmosphere, or corona, visible in the darkness.
The corona, lasting just two minutes, marks the peak phase of totality and the only stage of the eclipse safe to view with the naked eye.
The path of the eclipse will take it across the Atlantic, with a partial eclipse crossing parts of Europe – later in the night.
BBC have an eclipse calculator which says that the next time people in Malta will be able to see an eclipse will be on June 21, 2020, when an annular eclipse will be visible, while the total eclipse in August 2027 will be visible from just to the south of Malta, giving locals on the island around a 90% experience.
