Every year, on the first two days of November, images of monarch butterflies pop up across Mexico. People wear orange-and-black monarch costumes and paint their faces like butterflies. It’s all part of the Mexican holiday Día de los Muertos, or Day of the Dead!

On this day, communities across the country dance and share food as they remember friends and family members who have passed away. Monarch butterflies are one of the symbols of the holiday. The insects are thought to carry the souls of departed loved ones.

It happens every year. Images of monarch butterflies pop up across Mexico. People wear orange-and-black monarch costumes. They paint their faces like butterflies. It’s all part of the Mexican holiday Día de los Muertos. That means Day of the Dead! It takes place the first two days of November.

People across the country dance to celebrate. They share food. And they remember those who’ve passed away. Monarch butterflies are a symbol of the holiday. The insects are thought to carry the souls of lost loved ones.

As these celebrations take place, real monarchs arrive in Mexico too. Every fall, they come by the millions from the U.S. and Canada. In the forests of central Mexico, the butterflies blanket tree trunks and branches. They rest in these forests until they leave in the spring.

But in recent years, monarchs have been struggling to find places to rest. As a result of habitat loss and other threats, monarchs are now endangered. That’s why residents of San Miguel Atlautla, a small town in Mexico, have taken action. Volunteers there are working to protect the monarchs that arrive in their area—and share why the insects are incredible!

Real monarchs come to Mexico around this time too. Millions fly from the U.S. and Canada every fall. They land in the forests of central Mexico. They cover tree trunks and branches. They rest in these forests. Then they leave in the spring.

But monarchs have been struggling in recent years. It’s harder to find places to rest. Their habitats, or natural homes, are disappearing. Now monarchs are endangered. That’s why a small town in Mexico has taken action. The town is named San Miguel Atlautla. People there are protecting monarchs that arrive in their area. They’re also sharing why the insects are amazing!

Most monarchs spend winter in forests west of Mexico City. In the past, only a few butterflies appeared in San Miguel Atlautla, 150 miles east of their normal nesting grounds.

But about 15 years ago, more butterflies began appearing in Atlautla. Residents had an idea for why that might be. “They came here because people in other places were cutting trees illegally,” says Gregorio Granados Baz. He heads the group that manages a protected area called Joya Redonda Monarch Butterfly Sanctuary.

Most monarchs spend winter in forests west of Mexico City. Only a few butterflies came to San Miguel Atlautla in the past. It’s 150 miles east of their normal nesting grounds.

But more butterflies began showing up about 15 years ago. People had an idea why that might be. “They came here because people in other places were cutting trees illegally,” says Gregorio Granados Baz. He heads the group that runs a protected area. It’s called Joya Redonda Monarch Butterfly Sanctuary.

The sun rises on a crisp fall morning in Missouri. You spent the night resting in a pine tree with dozens of fellow monarch butterflies. It was too cold in the dark for you to fly.

When the temperature is below 54°F (12°C), you can’t flex your wing muscles. But with the warmth of the morning sun, you’ll soon be able to take off on your own.

How did you get here? You hatched as a caterpillar about two months ago in a garden in Ohio, nearly 1,000 miles (1,609 km) away. Two weeks ago, you left your chrysalis as an adult butterfly. When the nights grew longer and colder, you knew you had to leave. Every day, you fly another 100 miles (161 km). You’ve never made this journey before. But instinct tells you exactly where to go next.

The sun rises. It’s a crisp fall morning in Missouri. You spent the night resting in a pine tree. Nearby are dozens of fellow monarch butterflies. It was too cold in the dark. You couldn’t fly.

Temperatures fell below 54°F (12°C). That made it so you couldn’t flex your wing muscles. But the morning sun is warm. You’ll soon be able to take off.

How did you get here? You hatched as a caterpillar. That was about two months ago. You lived in a garden in Ohio. That’s nearly 1,000 miles (1,609 km) away. You left your chrysalis two weeks ago. You were now an adult butterfly. The nights grew longer and colder. You knew you had to leave. You fly another 100 miles (161 km) every day. You’ve never made this trip before. But somehow you know exactly where to go.