For many people, the night of October 31 is a time for trick-or-treating. But for millions of Americans, it’s also the start of Día de los Muertos, or the Day of the Dead. Despite the name, the three-day holiday is a celebration of life too. Many people believe the spirits of their dead relatives return to visit during that time.

Día de los Muertos originated in Mexico, where it’s a national holiday. Today, it’s celebrated across the U.S. by people of Mexican heritage too. 

To welcome their lost loved ones, families create altars called ofrendas in their homes. They decorate the altars with flowers, candles, and photographs, and they might set out their dead relatives’ favorite foods and drinks. Many people also clean and decorate the graves of their relatives and hold feasts there too. 

Skeletons are also a big part of the holiday. People often decorate ofrendas and graves with colorful skulls and eat skull-shaped treats. Several U.S. cities hold Day of the Dead parades, where people march in skeleton costumes. They aren’t meant to scare anyone. Instead, they’re a joyful reminder that death is a part of life.