They were seeing red.

A total lunar eclipse was visible to more than three billion people in the sky on Tuesday morning, with the moon glowing a spectacular shade of blood-red.

“It’s as if all of the world’s sunrises and sunsets are projected onto the moon,” NASA said in a statement, describing the phenomenon that occurs when the Earth sits between the moon and the sun.

On Tuesday, the best vistas in North America occurred in the west, with skygazers in Vegas treated to awe-inspiring views in the hours before dawn.

Parts of Australia, New Zealand, South America, Asia and Europe also saw the eclipse, with millions setting their alarms to witness the phenomenon in all its glory.

LAS VEGAS, NEVADA: The Las Vegas Sphere turned into a giant Blood Moon to mark the total lunar eclipse. The entertainment center is seen in the foreground, as the real moon glows a bright yellow behind it. Brian Prahl / Norene Prahl / SplashNews.comLAS VEGAS, NEVADA. The total lunar eclipse is seen against Sin City’s High Roller early Tuesday morning. APSEOUL, SOUTH KOREA: Skywatchers in Seoul were treated to an incredible view of the blood moon on Tuesday. It is pictured passing behind the N Seoul Tower. REUTERSAHMEDABAD, INDIA: Indians interested in astronomy awoke early to see the blood moon in the sky shortly before dawn. APBUENOS AIRES, ARGENTINA: The moon rises in its waxing gibbous phase behind a building in Buenos Aires. AFP via Getty ImagesAUCKLAND, NEW ZEALAND: New Zealand got a full, start-to-finish view of the total lunar eclipse. Getty ImagesSANTA ROSA, PHILIPPINES: Totality lasted for approximately 59 minutes as the lunar disk transformed into a blood moon, as it bathed in the red-orange refracted light of every sunset and sunrise happening on Earth. Getty ImagesSALAMINA ISLAND, GREECE: The phenomenon was also visible on Salamina Island off the coast of Athens. APLA PAZ, BOLIVIA: The total lunar eclipse is pictured over La Paz, the highest administrative capital in the world, resting on the Andes’ Altiplano plateau at more than 3,500m above sea level. Esteban Biba/EPA/ShutterstockSOUTH PORTLAND, MAINE: The view wasn’t quite as spectacular along the East Coast of the US, but three men did get to see a partial eclipse on a very chilly Tuesday morning. APGOLAGHAT, ASSAM: This multiple exposer picture shows the moon during the total lunar eclipse. AFP via Getty Images