Photo of the day

Tumbes, Peru: Maria tells Rachel Brosnahan about her hopes for her son's education. This image is from Activate: The Global Citizen Movement.

Mummy stored in the ICA's regional museum in Peru. This image is from The Last Secrets of the Nasca.

Sky, a Pitbull Boxer puppy, feels sick after potentially eating something toxic. This image is from The Incredible Dr Pol.

Millie the Eclectus is in to see Dr. Susan Kelleher for her exploratory surgery. This image is from Dr. K's Exotic Animal ER.

Deformed skulls, typical of the Nasca and Paracas civilisations. This image is from The Last Secrets of the Nasca.

Bonang Matheba jokes with students at Thabotona Primary Farm School. This image is from Activate: The Global Citizen Movement.

(Left to Right) Camera Operator Ronald Rose, Director of Photography BJ Golnick and Co-Executive Producer Chris Cassel film in front of El Castillo at Chichen Itza. This image is from Buried Truth of the Maya.

Bindi the corn snake has a mysterious lesion on the top of her head. This image is from Dr. K's Exotic Animal ER.

Stonehenge was built in three phases beginning about 3,100 B.C. This image is from Stonehenge Decoded: Secrets Revealed.

Uzo Aduba demonstrates how to use P&G Purifier of Water packets. This image is from Activate: The Global Citizen Movement.

A trophy head stored in the anthropological national museum of Lima in Peru. This image is from The Last Secrets of the Nasca.

Deerfield Beach, FL: Close up of Peanut, the one-year-old ferret. This image is from Dr. K's Exotic Animal ER.

A client holds his Leopard Gecko that is suffering from eye issues. This image is from The Incredible Dr Pol.

The facade of Ad-Dier, or the Monastery, in the ancient city of Petra. This image is from Petra: Secrets of The Ancient Builders.

Surrounded by stalactites, the Virtual Wonders team dives underneath the surface of Holtun cenote to guide an underwater ROV into small crevices humans can't safely reach. This image is from Buried Truth of the Maya.

Daren Criss (right) jokes with a local fisherman. The World Bank estimates there are 25 to 27 million "small scale fishers" around the world, and many of them are disproportionately affected by ocean plastic pollution. This image is from Activate: The Global Citizen Movement.

Kehlani the Marmoset waits patiently for Dr. Veronica Pardini to announce Kehlani's gender. This image is from Dr. K's Exotic Animal ER.

Corazon del Sol and Linda Franke sitting on the front steps of their home and petting Lou. This image is from Dog: Impossible.

The Nasca Lines of Peru: ancient images of animals and vast geometric designs etched in the desert ground – have mystified the world for nearly a century. Some have speculated that aliens built them. Employing drone camera technology, Peruvian archaeologists Luis Jaime Castillo and Johny Isla have discovered even older lines in the Atacama Desert, some more than 2000 years old. Unlike the known Nasca Lines, these older lines depict humans, such as dancers and warriors. This image is from Nasca Lines: Unlocking The Secrets.

Brooklyn, NY: Wade McMullen, a lawyer with RFK human rights, explains the problem of money bail to Common as Kerry Kennedy and Katie Dallas look on. This image is from Activate: The Global Citizen Movement.

Stonehenge in the evening. This image is from Stonehenge Decoded: Secrets Revealed.

Dr. Sara Stoneburg sedates Maya the Blue-Tongue Skink for her diagnostic exams. This image is from Dr. K's Exotic Animal ER.

Aerial view of Mayan ruins at Chichen Itza. This image is from Buried Truth of the Maya.

Hugh Jackman meets with the Global Citizen team. This image is from Activate: The Global Citizen Movement.

Dr. Pol checks camel for pregnancy with the help of Peggy. This image is from The Incredible Dr Pol.

Matt Beisner, host of National Geographic's Dog: Impossible. This image is from Dog: Impossible.

The Nasca Lines of Peru: ancient images of animals and vast geometric designs etched in the desert ground – have mystified the world for nearly a century. Some have speculated that aliens built them. Employing drone camera technology, Peruvian archaeologists Luis Jaime Castillo and Johny Isla have discovered even older lines in the Atacama Desert, some more than 2000 years old. Unlike the known Nasca Lines, these older lines depict humans, such as dancers and warriors. This image is from Nasca Lines: Unlocking The Secrets.

Becky G poses with the women's weaving collective. This image is from Activate: The Global Citizen Movement.

Deerfield Beach, FL: Xenon the Fennec Fox is waiting to be treated by Dr. Lauren Thielen for her dislocated wrist. This image is from Dr. K's Exotic Animal ER.

An aerial view of the ruins of the Great Temple in the ancient city of Petra. This image is from Petra: Secrets of The Ancient Builders.