Millions of Americans have witnessed a phenomenon dubbed the “eclipse of the century” as much of the west cost of the United States was plunged into darkness Tuesday morning (AEST).

Armed with telescopes, cameras and protective glasses, Americans in 14 states staked out viewing spots to watch on as the moon blocked out the midday sun.

The event, the first total solar eclipse to sweep coast-to-coast across the US in 99 years, is expected to be the most observed and documented natural event in history.

“It’s really, really, really, really awesome,” said nine-year-old Cami Smith as she watched the fully eclipsed sun from a gravel lane near her grandfather’s home at Beverly Beach, Oregon.

The temperature dropped, birds quieted down, crickets chirped and the stars came out in the middle of the day as the line of darkness raced 4200 kilometres across the continent in about 90 minutes, bringing forth oohs, aahs, shouts and screams.

In Boise, Idaho, where the sun was more than 99 per cent blocked, people clapped and whooped, and the street lights came on briefly, while in Nashville, Tennessee, people craned their necks at the sky and knocked back longneck beers at Nudie’s Honky Tonk bar.

Watch our time lapse of the 2017 Total Solar #Eclipse as it passed over the Museum and downtown #KansasCity. pic.twitter.com/3hUqgDFuUU

— National WWI Museum (@TheWWImuseum) August 21, 2017

Many crowds gathered in cities and towns near the “zone of totality,” a band about 100 kilometres wide from Oregon to South Carolina where the sun’s rays were completely blocked by the moon.

Mr Trump ignored warnings and looked at the eclipse without safety glasses. Photo: Getty

President Donald Trump witnessed the event with his family and staff at the White House, wearing the obligatory protective glasses.

Despite all the warnings from experts about the risk of eye damage, President Donald Trump took off his eclipse glasses and looked directly at the sun.

At the Nashville Zoo, the giraffes and rhinos started running around crazily when the sun came back.

Several minor-league baseball teams – one of them, the Columbia Fireflies, outfitted for the day in glow-in-the-dark jerseys – briefly suspended play.

The eclipse has been anticipated for months as it is the first coast-to-coast solar eclipse in the United States since 1918.

But just before and just after ‘totality’, viewers were treated to the classic features of a total solar eclipse, including “Bailey’s Beads” which arise as the last shafts of sunlight drive through valleys on the Moon; and the “Diamond Ring”, which is the single brilliant point of light that signals the beginning and end of totality.

Eclipse watchers were treated to the classic show, Photo: Getty

Numerous events were planned – including a cruise during which music artist Bonnie Tyler was to perform her 1980s hit Total Eclipse of the Heart”.

The Atlantic coastal city of Charleston was the final major urban area to see the eclipse at  2.47pm local time.

The next total solar eclipse on Earth is on July 2, 2019 over the South Pacific, Chile and Argentina.

– With agencies