Thousands turned their eyes to the sky on both sides of the Pacific to gaze excitedly as a partial eclipse occluded the sun at dawn in Asia and at dusk in the western United States.
The eclipse began over southern China early Monday before moving westwards towards Japan, and was continuing across the Pacific towards North America late Sunday local time.
Clouds across much of eastern China prevented a clear view, with some early risers in Hong Kong able to see only a small sliver of the "annular" eclipse and others coming away disappointed.
An annular eclipse occurs when the moon passes in front of the sun, but is too far from the Earth to block it out completely, leaving a "ring of fire" visible.
But hundreds in Tokyo got a spectacular sight of the Japanese capital's first glimpse of the phenomenon in 173 years.
Sadanobu Takahashi, 60, from Japan's northern Akita prefecture, said he and his wife joined a special two-day tour of Tokyo to watch the eclipse from the top of a 54-floor building in the Roppongi district.
"Look! Now it's a perfect ring. How wonderful!" he cried out.
Around 200 people were gathered on the roof terrace, where two-year-old Hikaru Ichikawa jumped up and ran around with special viewing glasses designed to protect his eyes, shouting: "I can see it! I can see it!"
Commuters from businessmen to schoolchildren stopped on the streets of Tokyo to watch as the eclipse developed, cheering when it became visible.
Japanese electronics giant Panasonic sent an expedition to the top of Mount Fuji, 3,776 metres (12,388 feet) high, to film the phenomenon using solar-powered equipment.
"Our goal in this project is to broadcast the world's most beautiful annular eclipse from the highest mountain in Japan," the company said.
A climbing team took high-capacity rechargeable batteries to the base camp, and was planning to use the power of the sun to "broadcast this moment of a century from the top of Mt. Fuji".
In Hong Kong, a few thousand optimistic early birds gathered on the Victoria Harbour waterfront hoping to catch a glimpse of the spectacle, but were denied by total cloud cover.
But while others higher up in Hong Kong were able to get a small glimpse through the clouds, the best that the would-be viewers on the harbourfront could do was take photos of each other holding up their protective filters.
Thousands in the western United States were banking on clearer skies as they ventured out at sunset on Sunday.
One of the best spots in North America to see the full ring of fire effect was the tiny town of Kanarraville, Utah, where the local population of 350 was invaded by thousands of eclipse-watchers.
"I looked along the (eclipse path), and the West Coast is always misty and New Mexico was too high on the horizon," David Lee, a member of the Royal Astronomical Society from Victoria, Canada, told the Salt Lake Tribune.
"I thought Utah was as good a gamble as any," he told the newspaper in the town, some 230 miles south of Salt Lake City.
Further west in Los Angeles, thousands gathered at a viewing party at the Griffith Observatory, a hill-top star-gazing centre popular with tourists, overlooking the city and the nearby Hollywood sign.
Amid cloudless southern Californian skies, the moon was expected to cover 86 percent of the solar diameter at the eclipse peak, leaving a thin sliver of the sun in the sky, an hour two before sunset.
The observatory ran out of $2.99 eclipse glasses two days before the event, and on Sunday was only selling larger "solarama" shields, limited to two per family to see the eclipse, the most spectacular in LA for 20 years.
One of the most ambitious projects to mark the moment was being mounted by electronics giant Panasonic, which had sent an expedition to the top of Mount Fuji to film the phenomenon using solar-powered equipment.