British holidaymaker Sean Chinn captures a crocodile on camera during a dive at the Jardines de la Reina marine park in Caribbean Sea, Cuba. (Photo by Sean Chinn/Caters News Agency)

16-year-old panda, Ye Ye, rests in an enclosure at the Wolong Nature Reserve, a conservation center that trains pandas for release into the wild. This image was published in the August 2016 National Geographic magazine as part of the “Pandas Gone Wild” story. (Photo by Ami Vitale/National Geographic Creative)

Behaviour: Mammals category. Giant Gathering by Tony Wu, USA. Dozens of sperm whales mingled noisily off Sri Lanka’s northeast coast, stacked as far down as Tony could see. This was a congregation of dozens of social units, like a gathering of the clans. Aggregations like this could be a critical part of the whales’ rich social lives but are rarely reported. Some two thirds of the population was wiped out before commercial whaling was banned in 1986. This kind of major gathering could be “a sign that populations are recovering”, says Tony. (Photo by Tony Wu/Wildlife Photographer of the Year 2017)

Kiritimati is a far-flung outpost of the Republic of Kiribati. The world's largest coral atoll, Kiritimati has just one flight a week to either Fiji or Hawaii, four-and-a-half hours in either direction. Tarawa, the capital of Kiribati lies nearly 3,300 km (2,000 miles) to the west – about three weeks by boat. No lawyers are based on Kiritimati and the High Court only comes once or twice a year to clear a backlog of the most serious cases, bringing a public lawyer for defendants who can't afford their own. (Photo by Lincoln Feast/Reuters)

Workers collect fish inside an abandoned department store in Bangkok, Thailand January 13, 2015. Staff from Bangkok Metropolitan Administration (BMA) office were catching fish on Tuesday at the ground floor of the roofless New World department store that was closed down in 1997. Thousands of fish such as catfishes, fancy carps as well as black and red tilapias were released into the ground floor of the building, flooded with rainwater, as local vendors tried to control mosquitoes in the area, local media reported. BMA recently decided to remove the fish and release the water. (Photo by Chaiwat Subprasom/Reuters)

An environmental activist performs during a protest in front of the headquarters of Brazilian mining company Vale SA in downtown Rio de Janeiro, Brazil, November 16, 2015. The collapse of two dams at a Brazilian mine, owned by Vale SA and BHP Billiton Ltd, has cut off drinking water for quarter of a million people and saturated waterways downstream with dense orange sediment that could wreck the ecosystem for years to come. Nine people were killed, 19 are still listed as missing and 500 people were displaced from their homes when the dams burst at an iron ore mine in southeastern Brazil on November 5. (Photo by Sergio Moraes/Reuters)

A 10-year-old pet goldfish named George undergoes veterinarian Tristan Rich's scalpel to remove a life-threatening head tumor in this handout picture taken September 11, 2014 and provided to Reuters by the Lort Smith Animal Hospital in Melbourne, Australia. In a 45-minute long procedure described by Rich as “fiddly”, the fish was sedated by water laced with anaesthetic, the tumour removed and the wound sealed with tissue glue followed by antibiotics and painkillers. (Photo by Reuters/Lort Smith Animal Hospital)

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)