Encyclopedia Britannica editions are seen at the New York Public Library on March 14, 2012 in New York City. Encyclopedia Britannica announced it will be ceasing its print edition of reference books for the first time in its 244-year history to focus solely on digital versions. (Photo by Mario Tama/Getty Images)

Ultra Orthodox Jews celebrate the Jewish holiday of Purim on March 8, 2012 in Benei Brak, Israel. The carnival-like Purim holiday is celebrated with parades and costume parties to commemorate the deliverance of the Jewish people from a plot to exterminate them in the ancient Persian empire 2,500 years ago, as described in the Book of Esther. (Photo by Uriel Sinai/Getty Images)

Heesco, Windsor. Born and raised in Mongolia and now living and working in Melbourne, Heesco is well known for his skill in rendering photo-realistic portraits. They speak to the viewer in a way that the subtext is enjoyable to decipher. Just what is the Blue Lady’s message? The sunglasses might mask the confronting gaze but her body language fills in the gaps. Heesco’s characters often wear traditional jewellery and clothing that remind us of his Mongolian cultural heritage. (Photo by Lou Chamberlin/The Guardian)

In this June 29, 2016 file photo, boats docked at Central Marine in Stuart, Fla., are surrounded by blue green algae. The 153-mile-long Indian River Lagoon has been plagued by harmful algae blooms. Water quality testing data analyzed by the AP showed the average phosphorous level – a byproduct of fertilizers and human waste that algae thrive on, rose nearly 75 percent between 2000 and 2016. (Photo by Greg Lovett/The Palm Beach Post via AP Photo)

These images show off some of the world's most majestic creatures silhouetted against the beautiful rising and setting sun. The vibrant pictures feature a variety of animals in the wild and were taken by a host of photographers at locations around the world. The striking images all have one thing in common: the photographers' awe-inspiring ability to perfectly capture the silhouettes of earth's beautiful creatures. Here: a blue wildebeest moves through grassland at dawn with the sun in the background in Mara Naboisho Conservancy, Kenya, Africa. (Photo by Renato Granieri/Caters News/Ardea)

Vanessa Silva, 38, feeds macaws that fly to her apartment window every day looking for food, in Caracas, Venezuela, on November 24, 2014. A group of gold-and-royal blue birds poked their heads through Silva’s window, as if saying “I’m here, is anyone home?” “I’d seen them flying when I was down on the street, and I thought ‘Oh how pretty,’” the 38-year-old said, a macaw eating out of her hand. (Photo by Ariana Cubillos/AP Photo)

A student attending a winter military camp reacts during a training session in Ansan, south of Seoul January 3, 2013. Hundreds of students between 11 and 17 years old attend winter boot camp training courses every year. The winter courses range from 4 to 14 days at the Blue Dragon Camp run by retired marines, which also offers summer boot camp for students. (Photo by Kim Hong-Ji/Reuters)

Ngorongoro Crater (Tanzania). At 610m deep and 260 sq km, this is the largest unflooded caldera in the world. A blue-green vision from above it's a haven for engangered wildlife and Maasai livestock. The crater was formed three million years ago when a giant volcano, which could have been as high as Kilimanjaro, exploded and collapsed. The caldera formed the concentric fractures in the crust cracked down to a magma reservoir deep underground. (Photo by John Bryant/Getty Images)