Emotion in the stands here is not unusual, but the noise that came from the bleachers at 3.06pm was something completely different.

The nearly 50,000 spectators knew roughly what to expect, aware that at the period of totality the moon would completely obscure the sun, plunging the arena into darkness.

But first-time eclipse watchers were overcome by the feeling.

Many of them began to cry as the sky suddenly darkened, turning afternoon into night-time in a matter of minutes.

The air chilled and people cheered loudly as the final portion of the sun was extinguished by the shape of the moon. Some took pictures on their mobile phones but many simply absorbed the moment.

"It was eerie, I've never seen anything like it," one woman tells me, wiping away tears. "You just had to be here."

"I was crying because of that feeling of awe," Archana Thakur says.

"I totally underestimated it. I had goosebumps. I only came because my husband and daughter wanted to come but I'm so pleased I did."

Eyewitness: 'Celestial serendipity' - eclipse was a breathtaking and unifying moment

She and her family drove five hours from Milwaukee, Wisconsin, to be in the path of totality.

Her 10-year-old daughter, Sanvi, is a budding scientist and spent much of the day enjoying the NASA exhibitions temporarily dotted around the Speedway before watching the eclipse.

"It was breathtaking, majestic and once in a lifetime," she tells me.

"I'm really interested in space so I researched a bit online but it was way more awesome than I expected."

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'I definitely cried'

The total solar eclipse isn't just a spectacle, it also offers scientists a rare opportunity to study its effects on the Earth.

John Waggle was at the Speedway leading a team of student scientists from Purdue University in Indianapolis.

An hour before the eclipse, they launched three weather balloons from the track more than 100,000ft into the sky.

They hope to collect data to assess how solar eclipses impact the Earth's atmosphere, looking at radiation, temperature changes and pressure.

"I've seen a partial eclipse before," John says.

"But seeing this one is completely different. It's like watching a concert live versus on TV. You can't replicate feeling the air cool off, the breeze whipping through, and seeing the stars."

His fellow student, Aubra Bailey, was similarly impressed. "It's definitely the most incredible thing I've ever seen and probably ever will see," she says.

People from all 50 states travelled to the speedway, with tickets sold in 21 different countries.

I saw toddlers and 90-year-old granddads waiting for the same moment of totality to arrive.

"It's a very bipartisan moment that we had here today," one man says, as he makes his way to the exit.

"Everyone here was rooting for the same thing. In our country there's a lot of bad things going on, but for one moment we were all together enjoying it.

"I definitely cried, I thought it was tears-worthy."

The last eclipse in Indianapolis was in the 13th century. The next will be in 129 years so it was an experience to savour and one which, for many, will not be repeated.