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)

Gers, traditional Mongolian tents, are seen on a hill in an area known as a ger district in Ulan Bator June 26, 2013. Approximately 60 percent of the population of Ulan Bator live in settlements known as ger districts and in many cases residents have limited access to basic services such as water and sanitation. According to a 2010 National Population Center census, every year between thirty and forty thousand people migrate from the countryside to the capital Ulan Bator. Ger districts in the city have been expanding rapidly in recent years. Mongolia is the world's least densely populated country, with 2.8 million people spread across an area around three times the size of France. (Photo by Carlos Barria/Reuters)

Photographer Carlos Barria holds a print of a photograph he took in 2005, as he matches it up at the same location 10 years on, in Lafitte, south of New Orleans, United States, August 16, 2015. The print shows Tyler Teal cleaning up his home, September 14, 2005, after Hurricane Katrina struck. In 2005, Hurricane Katrina triggered floods that inundated New Orleans and killed more than 1,500 people as storm waters overwhelmed levees and broke through floodwalls. (Photo by Carlos Barria/Reuters)

The Bahamas, the Commonwealth nation of hundreds of islands roughly the size of Connecticut and with population of just a bit over Anaheim, is known for its crystal waters and pristine beaches. This is possibly one of the world’s most beautiful havens of nature, yet people are coming here to see pigs. It is unclear when the pigs first appeared on Exuma Island or where they come from. There’s talk about a daring escape from a shipwreck, or sailors releasing the swine on purpose. In all probability, there were no pigs on this tropical paradise before European settlers came, so their mere presence is the work of human. The intriguing feat of nature, however, is that this population of pigs developed a fine aptitude for swimming. Here: “So you're on a boat in Bahamas and then this pig swims by begging for food”. (Photo and caption by Lisa Larsen/Public Domain)

The Mexican ship Cuauhtemoc is pictured during the Tall Ships Races 2016 parade, in Lisbon, Portugal, July 25, 2016. The Tall Ships' Races are races for sail training “tall ships” (sailing ships). The races are designed to encourage international friendship and training for young people in the art of sailing. The races are held annually in European waters and consists of two racing legs of several hundred nautical miles, and a “cruise in company” between the legs. Over one half (fifty-percent) of the crew of each ship participating in the races must consist of young people. (Photo by Pedro Nunes/Reuters)

An area of vegetation can be seen amongst drought effected farmland in South Australia, November 12, 2015. A pioneering Australian scheme to improve the management of water in the world's driest inhabited continent is facing its first real test as an intensifying El Nino threatens crops and builds tensions between farmers and environmentalists. An El Nino, a warming of sea-surface temperatures in the Pacific, is already causing drought and other extreme weather, affecting millions of people across parts of the world, and experts warn that the intensifying weather pattern could emerge as one of the strongest on record. (Photo by David Gray/Reuters)

A man tries to stop two bulls from locking horns during a bullfight in the eastern emirate of Fujairah October 17, 2014. There are no matadors or picadors, but bulls locking horns with each other draw big crowds to bullfights in the United Arab Emirates (UAE). An hour's drive from the dancing water fountains of Dubai's glitzy downtown, hundreds of fans gather in Fujairah to watch bulls fighting, or perhaps more accurately head butting, with honour rather than money at stake. The UAE sport involves two bulls locking horns in a three-to-four minute Sumo-wrestling-like fight that usually ends with no bloodshed. (Photo by Ahmed Jadallah/Reuters)

A girl who suffers from hearing and speech disorders reacts to the camera at a rehabilitation centre supported by Bhopal Medical Appeal, for children who were born with mental and physical disabilities, in Bhopal November 11, 2014. The rehabilitation centre only treats families they believe have been affected by the Union Carbide gas leak 30 years ago. Human rights groups say that thousands of tonnes of hazardous waste remain buried underground, and the government has conceded it is contaminated. There has, however, been no long-term epidemiological research which conclusively proves that birth defects are directly related to the drinking of the contaminated water. (Photo by Danish Siddiqui/Reuters)