NASA says it could be another 20 years before humans touch down on Mars, but in a sense, the Mars Society has been exploring the red planet for more than a decade – in Utah. Photo: Csilla Orgel, a geologist of Crew 125 EuroMoonMars B mission, makes her way back to the Mars Desert Research Station (MDRS) in the Utah desert March 3, 2013. The MDRS aims to investigate the feasibility of a human exploration of Mars and uses the Utah desert's Mars-like terrain to simulate working conditions on the red planet. Scientists, students and enthusiasts work together developing field tactics and studying the terrain. All outdoor exploration is done wearing simulated spacesuits and carrying air supply packs and crews live together in a small communication base with limited amounts of electricity, food, oxygen and water. Everything needed to survive must be produced, fixed and replaced on site. (Photo by Jim Urquhart/Reuters)

Legend has it that the Irish warrior Fionn mac Cumhaill (Finn McCool) built the causeway to walk to Scotland to fight his Scottish counterpart Benandonner. One version of the legend tells that Fionn fell asleep before he got to Scotland. When he did not arrive, the much larger Benandonner crossed the bridge looking for him. To protect Fionn, his wife Oonagh laid a blanket over him so he could pretend that he was actually their baby son. In a variation, Fionn fled after seeing Benandonner's great bulk, and asked his wife to disguise him as the baby. In both versions, when Benandonner saw the size of the 'infant', he assumed the alleged father, Fionn, must be gigantic indeed. Therefore, Benandonner fled home in terror, ripping up the Causeway in case he was followed by Fionn.

Two keepers at the Australian Reptile Park in New South Wales struggle with Leonardo, an alligator snapping turtle weighing 45 kilos at the park in Gosford, NSW 2 July 2015. The 50cm long Leonardo – who was smuggled illegally into Australia and found in a Sydney sewer in November 2000 – was removed from his tank for an annual health check. And as a gesture to onlooking press photographers demonstrated his strength by snapping a piece of bamboo in half. (Photo by EPA/HO)

Israeli fashion design student from the Shenkar College of Engineering and Design Danit Peleg (R) assists a fashion blogger to wear an outfit from her graduate collection during a conference on 3-D printing in Tel Aviv, Israel September 3, 2015. Peleg, 27, says she spent over 2000 hours to create her graduate collection which is made solely from home 3-D printers. International fashion bloggers, taking part in a project supported by “Stand With Us Israel fellowship”, a non-profit organisation, attended the conference and tried on Peleg's clothing before listening to her talk about her collection. (Photo by Nir Elias/Reuters)

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?

A brown-hooded kingfisher sits on a branch with a freshly caught frog in it's beak. Riaan Marais who took the photo said, “We were doing a boat safari on the Rufiji river in Selous Game Reserve, Tanzania when I spotted the bird with the frog on an overhanging branch on the river bank. It most probably caught the frog in the reeds along the river’s edge as this is where these frogs stay. The kingfisher must have caught the Common Reed Frog just before I took the image, as the frog was still alive, I had a brief moment to take the image before the bird flew off with the frog”. (Photo by Riaan Marais/Solent News and Photo Agency)

“Jacob «Jack» Kevorkian (May 26, 1928 – June 3, 2011), commonly known as “Dr. Death”, was an American pathologist, euthanasia activist, painter, composer and instrumentalist. He is best known for publicly championing a terminal patient's right to die via physician-assisted suicide; he said he assisted at least 130 patients to that end. He famously said, «dying is not a crime»”. – Wikipedia

Photo: The “Thanatron”, often referred to as the “Death Machine”, is displayed during a press preview of an auction of the personal effects of Dr. Jack Kevorkian at the New York Institute of Technology on October 27, 2011 in New York City. The device was reportedly used by over 100 of Dr. Kevorkian's patients to terminate their lives. (Photo by Mario Tama/Getty Images)

Chinese artist Kong Ning poses in a costume symbolizing a butterfly, which is decorated with 365 masks on its wings to represent the number of days in a year, during her performance art at the Badaling section of the Great Wall on the outskirts of Beijing January 1, 2015. Kong, whose works include themes related to China's air pollution problem, named her new performance art “Hua Die” (transforming into a butterfly) and performed it on the first day of the new year as she hopes that China has clean air for this year. (Photo by Kim Kyung-Hoon/Reuters)