A total solar eclipse is expected to cross North America today, with parts of 15 U.S. states within the path of totality. Various maps show where and when astronomy fans can see the big event as skies darken in the middle of the day on Monday, April 8.

The total eclipse will first appear along Mexico’s Pacific Coast at around 11:07 a.m. PDT, then travel across a swath of the U.S., from Texas to Maine, and into Canada.

About 31.6 million people live in the path of totality, the area where the moon will fully block out the sun, according to NASA. The path will range between 108 and 122 miles wide. An additional 150 million people live within 200 miles of the path of totality.