Amateur astronomer Bill Snyder has been involved with astrophotography since 2007. Photo: The Cygnus Wall is in the southern area of NGC7000 also known as the North America Nebula. It is approximately 1800 light years from Earth, and is in the constellation Cygnus. The Wall is an energized shock front and contains the most concentrated star formations in the nebula. The size of the North America Nebula is about 4 full moons. (Photo and caption by Bill Snyder)

Denis Rouvre is a portraitist, living and working in France. His photos have been nationally and internationally published. Rouvre’s photo series have been widely exhibited in France and abroad. He has also published several books, and his numerous prizes include World Press Photo award, and a Sony World Photography Award. Photo: Asia Argento. (Photo by Denis Rouvre)

This is the amazing moment a heroic hippo saved a gnu from certain death. After being bitten by a crocodile, the large antelope is seen being dragged slowly under the water. But in a miraculous turn of events, a nearby hippo is seen making its way across the water to help the animal in its hour of need. Photo: One of the biggest hippos protects the gnu as it makes its way back to the shoreline, guarding it from any further attacks. (Photo by Vadim Onishchenko/Caters News)

A woman dressed as a cleaning lady laughs during “Weiberfastnacht” (Women's Carnival) in Cologne February 12, 2015. Women's Carnival marks the start of a week of street festivals, the highlight of the event being “Rosenmontag” (Rose Monday), the final day of the carnival where mass processions are held. (Photo by Ina Fassbender/Reuters)

Baby clouded leopards, born early in March 2015, are presented by zoo keepers at the Olmense Zoo in Olmen, Belgium, April 16, 2015. The clouded leopard is an endangered species with only some 10,000 specimen remaining on earth, said Robby Van der Velden, a biologist at the Olmense Zoo. (Photo by Yves Herman/Reuters)

The Waitomo Glowworm Caves attraction is a cave at Waitomo on the North Island of New Zealand, known for its population of glowworms, Arachnocampa luminosa. This species is found exclusively in New Zealand. They are around the size of an average mosquito. This cave is part of the Waitomo Caves system that includes the Ruakuri Cave and the Aranui Cave.

Aviation enthusiast Patrick Wilson 8, from Wetherby looks at an Avro 504 k at “The Shuttlesworth Collection” at Old Warden on July 21, 2014 in Biggleswade, England. Of the 55,000 planes that were manufactured by the Royal Army Corps (RAC) during WWI, only around 20 remain in airworthy condition. Six of these belong to The Shuttleworth Collection at Old Warden, Bedfordshire, making it the most complete collection of original airworthy WWI aircraft in the world. Amongst the collection is the SE5a. The SE5a is a single seater fighter aircraft. It is an original biplane designed by the Royal Aircraft Factory, with its engine built by Wolseley Motors Ltd, and it was issued to 84 Squadron in November 1918. The National Archive in Kew has recently verified that the plane saw action in France with 84 Squadron the day before Armistice, November 10, 1918. (Photo by Dan Kitwood/Getty Images)

Some foods have significantly more Calories than others but what does the difference actually look like. Each of the photographs below represents 200 Calories of the particular type of food; the images are sorted from low to high calorie density. When you consider that an entire plate of broccoli contains the same number of Calories as a small spoonful of peanut butter, you might think twice the next time you decide what to eat. According to the U.S. Department of Agriculture, the average adult needs to consume about 2000 – 2500 Calories to maintain their weight. In other words, you have a fixed amount of Calories to "spend" each day; based on the following pictures, which would you eat?