Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Viana Scarlett Sanchez Arias from WWF collects live monarch butterflies in order to study them at WWF headquarters after which they will be released back into the wild. These samples are taken every 1...

Viana Scarlett Sanchez Arias from WWF collects live monarch butterflies in order to study them at WWF headquarters after which they will be released back into the wild. These samples are taken every 1...

A mural of monarch butterflies.

A mural of the town and monarch butterflies.

L-R: Marcello Valdez Martinez, Rogelio Gonzales Moreno, Francisco Ambrosio Martinez, Javier Martinez Colin, Eugenio Moreno Esquivel on a patrol carried out by people from the local community to monito...

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

A mural of monarch butterflies.

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

People on horses riding through a forest alive with monarch butterflies. Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Ro...

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

An abandoned caravan on the border between England and Scotland.

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

A patrol carried out by people from the local community, they monitor the forest and illegal logging in the Sierra Chincua monarch butterfly reserve.

Marcello Valdes Martinez sits among the undergrowth in the Sierra Chincua monarch butterfly reserve.

Monarch butterflies in the Sierra Chincua Reserve.

Trees covered with millions of monarch butterflies.

Millions of monarch butterflies flying after their annual migration.

Mayra Alsi Mendoza Perez and Maltin Cruz Peina, from WWF, measure the area of a monarch butterfly colony by measuring the distance between the trees that surround the colony.

Trees covered with millions of monarch butterflies.

Trees covered with millions of monarch butterflies.

Trees covered with millions of monarch butterflies.

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Palm wine tapper Samson Turay climbs up a palm tree near Bureh. The job of climbing palm trees to collect the precious sap traditionally falls to members of the Limba ethnic group.

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Palm wine tapper Samson Turay climbs up a palm tree near Bureh. The job of climbing palm trees to collect the precious sap traditionally falls to members of the Limba ethnic group.

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Walkers stop to look at birds next to the Ring of Brodgar, a circle of standing stones that is over 4,000 years old.

Sunrise over a misty grove of palm trees in the interior of Sierra Leone. The trees produce a mildly alcoholic sap known as palm wine, or 'poyo', a popular drink throughout West Africa. In Sierra Leon...

Sunrise over a misty grove of palm trees in the interior of Sierra Leone. The trees produce a mildly alcoholic sap known as palm wine, or 'poyo', a popular drink throughout West Africa. In Sierra Leon...

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Tamba Conteh, a veteran palm wine tapper, climbs a palm tree outside Freetown. Conteh hails from the Limba ethnic group, who have dominated the palm wine industry for hundreds of years. The sap from t...

Tamba Conteh, a veteran palm wine tapper, climbs a palm tree outside Freetown. Conteh hails from the Limba ethnic group, who have dominated the palm wine industry for hundreds of years. The sap from t...

Viana Scarlett Sanchez Arias from WWF measures a live monarch butterfly caught in order to study them at WWF headquarters. After they are examined they will be released back into the wild. These sampl...

Monarch butterflies in a forest.

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

A woman walks through a forest where monarch butterflies gather, wearing a monarch butterfly fabric dress.

A woman covered in monarch butterflies, wearing a monarch butterfly fabric dress.

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Every year, from January to the end of March, millions of monarch butterflies make a 4000 kilometre migration to breed in El Rosario where the world's largest colony of monarch butterflies are found....

Viana Scarlett Sanchez Arias from WWF collects live monarch butterflies in order to study them at WWF headquarters after which they will be released back into the wild. These samples are taken every 1...

Karin Ostertag and Dassi Bah, a Vodoun (Voodoo) adept, looking out over the Tobe protected forest. Some 350 hectares in area, the forest had been severely degraded by agriculture. Over the last 35 yea...

A tree silhouetted against the sky on a rock outcrop in the Tobe protected forest. Some 350 hectares in area, the forest had been severely degraded by agriculture. Over the last 35 years it has been r...

The heavily-textured bark of a tree trunk in the Tobe protected forest. Some 350 hectares in area, the forest had been severely degraded by agriculture. Over the last 35 years it has been restored tha...

A tree in a shaft of sunlight in the Tobe protected forest. Some 350 hectares in area, the forest had been severely degraded by agriculture. Over the last 35 years it has been restored thanks to a par...