On August 21, 2017, millions of Americans will get the chance to see a total solar eclipse. Technically, this cosmic phenomenon isn't all that rare — an eclipse can be seen from somewhere on this planet every 18 months or so. But to be able to watch the moon blot the sun right out of the sky from your particular spot on Earth? Well, that happens only once in a lifetime.

1961 | Crowds watch the total solar eclipse near Nice, France. | (Keystone Pictures USA/Alamy Stock Photo)

The last time the United Stated played host to that path of totality was in 1979. And this year's event will actually be the first time since 1918 that a total solar eclipse will be visible from coast to coast.

"This is the most awesome astronomical event there is, period," Mike Kentrianakis, a veteran eclipse chaser, told The New York Times. "You'll never ever forget it."

As the moon slowly makes its away across the sun, the darkening day takes on a mystical, ominous quality. The temperature drops. The wind picks up. The dimming sun creates an eerie twilight in hues rarely seen in the natural world. Then, you're plunged into darkness. Depending on where you are, the moment can last anywhere from a few seconds to just over two minutes.

"I had no idea that it was going to be so powerful and emotive and euphoric and exciting," eclipse-chaser Kate Russo told Vox. "It's very unlike another experience."

1927 | Crowds gather on a hill near Giggleswick, north Yorkshire, to view a total eclipse of the sun. | (Keystone/Getty Images)

Should you be one of the lucky millions, equipped with the proper safety glasses, looking up at the sky this Monday, take it from an expert, and resist the urge to capture it on your phone.

"[Missing the eclipse] would be to not live as full a life as you could have," said astrophysicist Neil deGrasse Tyson, who has been looking forward to this total solar eclipse since he was a 24-year-old college student. "And having video of it doesn't match watching it happen."

In honor of our modern celestial extravaganza, delight in these vintage photos of people living in the bizarre and brilliant moment of totality.

1912 | Policemen look at the solar eclipse in Berlin. | (Sueddeutsche Zeitung Photo/Alamy Stock Photo)

1925 | President Calvin Coolidge and first lady Grace Coolidge view the solar eclipse from White House Lawn. | (Glasshouse Images/Alamy Stock Photo)

1927 | A group gathers in a window to view the total solar eclipse over London through smoked glass. | (H. F. Davis/Topical Press Agency/Getty Images)

1927 | A schoolteacher instructs his students on how to safely view the solar eclipse in London. | (Kirby/Topical Press Agency/Getty Images)

1927 | A group of nurses observe a solar eclipse through special dark glasses in 1927 (location unknown). | (Fox Photos/Getty Images)

1936 | Amateur astronomers view an eclipse of the sun in Hornsey, London. | (E. Dean/Topical Press Agency/Getty Images)

1936 | Spectators at Upton Park, London, pause during a soccer match to view the eclipse of the sun. | (Topical Press Agency/Getty Images)

1952| A man watches an eclipse through a strip of exposed camera film in Sudan. | (Chris Ware/Keystone Features/Hulton Archive/Getty Images)

1961 | Students and their teacher watch the solar eclipse through toned glasses in Munich. | (dpa picture alliance/Alamy Stock Photo)

1961 | Several hundred people watch the solar eclipse in Europe. | (dpa picture alliance/Alamy Stock Photo)

1966 | A member of the Junior Astronomical Society observes an eclipse of the sun in the United Kingdom. | (Ronald Dumont/Express/Getty Images)