This month's full moon will be the year's first supermoon, an astronomical phenomenon where the moon is slightly closer to Earth and therefore appears bigger and brighter in the sky.

The Native American tribes in the South call a full moon occurring in March the "Worm" moon because of the earthworm casts -- soil that the worms digests -- which become visible as the ground thaws.

This year's "Worm" supermoon is the fourth brightest moon of 2021, according to Earth Sky. It was at its fullest at 2:48 p.m. ET on Sunday.

The moon is seen behind the Camlica Mosque in Istanbul, Turkey.
The moon is seen behind the Camlica Mosque in Istanbul, Turkey.
Emrah Gurel/AP
A couple are silhouetted against the rising full moon as they gather in a Kansas City, Missouri park on Sunday.
A couple are silhouetted against the rising full moon as they gather in a Kansas City, Missouri park on Sunday.
Charlie Riedel/AP
The moon appears between buildings behind Tower Bridge in Central London on Monday.
The moon appears between buildings behind Tower Bridge in Central London on Monday.
Tony Hicks/AP
The moon is seen above the Karancs Hills in Karancskeszi, Hungary, on Sunday, March 28.
The moon is seen above the Karancs Hills in Karancskeszi, Hungary, on Sunday, March 28.
Peter Komka/EPA-EFE/Shutterstock
The full moon stands between the twin towers of the Frauenkirche cathedral, in Munich, Germany.
The full moon stands between the twin towers of the Frauenkirche cathedral, in Munich, Germany.
Peter Kneffel/dpa/Reuters
Syrian kids stand on a vehicle under the moon at the Maarrat Misrin camp in Idlib province, Syria.
Syrian kids stand on a vehicle under the moon at the Maarrat Misrin camp in Idlib province, Syria.
Muhammed Said/Anadolu Agency/Getty Images
The worm moon is seen from Kearny, New Jersey, as it rises behind the Empire State Building and Hudson Yards in New York City.
The worm moon is seen from Kearny, New Jersey, as it rises behind the Empire State Building and Hudson Yards in New York City.
Gary Hershorn/Corbis News/Getty Images
The moon rises over Kars, Turkey.
The moon rises over Kars, Turkey.
Huseyin Demirci/Anadolu Agency/Getty Images
A cyclist in Los Angeles, California is silhouetted against the backdrop of the "Worm Moon".
A cyclist in Los Angeles, California is silhouetted against the backdrop of the "Worm Moon".
Ringo Chiu/AP
The moon rises over Moscow, Russia.
The moon rises over Moscow, Russia.
Sefa Karacan/Anadolu Agency/Getty Images
A women watches the moon during a sunrise at Monterrico beach in Santa Rosa, Guatemala, on Monday.
A women watches the moon during a sunrise at Monterrico beach in Santa Rosa, Guatemala, on Monday.
Esteban Biba/EPA-EFE/Shutterstock