This is the first total solar eclipse from mainland Europe since 1999, and about 15 million people will have the opportunity to witness it.

Greenland, Iceland, Russia, Portugal, and large parts of Spain will lie on the direct path of totality. In Spain, totality will begin at 8:27 PM local time and last about 110 seconds depending on the location. It will be most clearly visible from cities such as León, Valladolid, Zaragoza, Teruel, and Valencia, while nearly 99 percent of the Sun will be covered in Madrid and Barcelona.

Because the apparent sizes of the Sun and Moon from Earth are nearly equal, this magnificent sight is created. Although two to five solar eclipses occur each year, total solar eclipses are relatively rare—on average only 66 times per century, meaning they are visible about once every one and a half years.

According to Al Jazeera, outside the path of totality, a partial eclipse will be visible in parts of Western Europe, northwestern Africa, and the United States. In total, about 980 million people around the world will be able to enjoy this rare celestial event, at least partially.