Snapping pictures with cell phones, hundreds of New Yorkers and tourists gathered in the streets to watch the sun set in perfect alignment between rows of the skyscrapers for which the city is famous.

Right on schedule at 8:12 pm on Tuesday evening, the flaming orange ball could be seen perfectly framed by Manhattan's canyons of tall buildings on streets running east-west, such as 42nd Street, which runs through Times Square.

This spectacle happens four times a year for two days, about three to four weeks before and after the summer and winter solstices.

It has come to be known as "Manhattanhenge" after Stonehenge, the ancient monument in southern England where the sun also lines up perfectly during the solstices – the moments when the sun appears to reach either its highest or lowest point in the sky.

"It's a beautiful event. And it's some totally New York moment to do," said Jeanette Wolfson, a 47-year-old science teacher from Long Island who came into the city to take pictures for her students.

She said she would remind them that "it's not the sun actually setting. It is the Earth rotating out of the light into the darkness."

The event lures photographers with fancy lenses and regular New Yorkers and tourists who do not hesitate to stand in the streets for a few minutes, blocking traffic.

Patrick Batchelder, a 59-year-old photographer, said that what matters is sharing the special moment with others.

"The picture itself is not so important, just being around the crowd and seeing something unique in New York City," he said.

The city's American Museum of Natural History recommends viewing the phenomenon from 14th, 23rd, 34th, 42nd or 57th streets to take in how "the city is framing the sunset", as astrophysicist Neil deGrasse Tyson puts it.

The next time it happens will be on July 12. (AFP)