Prince Philip, Duke of Edinburgh practicing his bicycle polo technique, Windsor Great Park, Berkshire, 1964. (Photo by Norman Potter/Daily Express/Hulton Archive/Getty Images)

The secretive indri (Indri indri) of Madagascar, the largest living lemur. It is also critically endangered and highly evolutionarily distinct with no close relatives, which makes its branch one of most precarious on the mammal evolutionary tree. In the likely event that the indri goes extinct, we will lose 19m years of unique evolutionary history from the mammal tree of life. (Photo by Pierre-Yves Babelon/Aarhus University)

A giant panda named Kai Kai looks on as he opens a gift to celebrate his upcoming 14th birthday at the River Safari wildlife park in Singapore on September 10, 2021. (Photo by Roslan Rahman/AFP Photo)

The Slauerhoffbrug (English: Slauerhoff Bridge) is a fully automatic bascule bridge (aka tail bridge) in the city of Leeuwarden in the Netherlands. It uses two arms to swing a section of road in and out of place within the road itself. It is also known as the “Slauerhoffbrug ‘Flying’ Drawbridge”. A tail bridge can quickly and efficiently be raised and lowered from one pylon (instead of hinges). This quickly allows water traffic to pass while only briefly stalling road traffic. The deck is 15 m by 15 m. It is painted in yellow and blue, representative of Leeuwarden's flag and seal.

In a new project, an international group of photographers have joined forces to use their powerful images to raise awareness and funds to help stop the illegal wildlife trade. Here: Fennec foxes are captured for the illegal pet trade. This three-month-old pup was for sale in a market in southern Tunisia. (Photo by Bruno D'Amicis/Photographers Against Wildlife Crime/Wildscreen/The Guardian)

People take pictures of deer in the Phoenix Park in Dublin, Ireland December 5, 2016. (Photo by Clodagh Kilcoyne/Reuters)

An injured vulture is treated at the VulPro Vulture Rehabilitation Centre in Hartebeepoortdam in the Magalisburg region on September 15, 2015. Confined to southern Africa, just under 4,000 breeding pairs of Cape Vultures remain in the wild, mostly in South Africa, Lesotho and Botswana. Unless conservation efforts are successful, Africa's largest vulture species may be facing eventual extinction. (Photo by Mujahid Safodien/AFP Photo)