“Hippo Chase”. As we approached the camp the Selinda Reserve of northern Botswana our boat passed by a hippo resting in the water. I turned around to look back at the boat's wake and saw the hippo charging after us! The hippo must've been tired from an all-nighter because he was angry. He rose way up out of the water three times trying to chase our boat! He was coming at us with such force that he created a wake of his own. Photo location: Selinda Reserve of northern Botswana. (Photo and caption by Curtis Simmons/National Geographic Photo Contest)

Challenger Bulgarian heavyweight boxer Kubrat Pulev (R) lies in the ring after being knocked down by Ukrainian WBA, WBO, IBO and IBF heavyweight boxing world champion Vladimir Klitschko (L), who celebrates with his brother Vitali (2nd L), as referee Tony Weeks checks on him after their title fight in Hamburg, November 15, 2014. World heavyweight champion Vladimir Klitschko knocked out Bulgarian challenger Kubrat Pulev with a fierce left hook in the fifth round on Saturday to retain his IBF title and end his opponent's unbeaten record. (Photo by Fabian Bimmer/Reuters)

An aerial view of the Atibainha dam, part of the Cantareira reservoir, during a drought in Nazare Paulista, Sao Paulo state November 18, 2014. Brazil's worst drought in 80 years has left the Cantareira system, that provides greater Sao Paulo with most of its water, with the lowest water level on record, with daily rationing becoming common in the region's smaller cities, according to the state authorities and the two main reservoirs serving metropolitan Sao Paulo, South America's largest city, could dry out by February if relief does not arrive in the upcoming rainy season. (Photo by Nacho Doce/Reuters)

What would superheroes do if they had a part time job? Well… besides fighting crime, the powers of most superheroes aren’t exactly very useful. Sure, Flash would make a great delivery boy, delivering the freshest pizza in the world, while Thor might turn out to be a great smith (though judging by the way he handles his mallet, it is very unlikely), but in the end of the day, all these things are pretty useless. It sure is hard being a superhero when you have no villains to catch; especially if the only superpower that you have is lighting yourself on fire. Reducing you to a mere job of being used as fuel for cooking grilled chicken. Besides, it’s not exactly useful for catching villains either, if you don't plan on burning them alive… (Photo by Chow Hon Lam)

Demonstrators take part in a mass “face-sitting protest” outside the Houses of Parliament in central London on December 12, 2014, as they protest against changes to p*rnography regulations. An amendment to the 2003 Communities Act applies the same strict rules to p*rn bought online as those included in the guidelines set out by the British Board of Film Censors for DVDs. The new laws ban films that feature s*x acts, such as spanking, caning, strangulation, aggressive whipping, humiliation, and face-sitting. Ministers say the rules have been brought in to protect s*x workers. But campaigners say it is an attempt to censor and control the internet. Paid-for videos shot overseas and viewed online in the UK are not affected by the new rules, which were introduced on December 2, 2014. (Photo by Leon Neal/AFP Photo)

Electric cars sit charging in a parking garage at the University of California, Irvine January 26, 2015. “The Irvine Smart Grid Demonstration”, a $79 million project funded half by federal stimulus money and half by Edison and partners like UC Irvine, was launched in 2010. The $12 billion utility's research team Southern California Edison is testing everything from charging electronic vehicles via cell phone to devices that smooth out the power created by rooftop solar panels. Those are some of the roughly 60 projects in the works at Edison's Advanced Technology division. It has a small $19 million annual budget, but its influence far exceeds that. (Photo by Lucy Nicholson/Reuters)

EMT Christian Amoroso, wearing personal protective equipment (PPE), pauses while unloading COVID-19 patients at the Montefiore Medical Center Wakefield Campus on April 06, 2020 in the Bronx borough of New York City. A specialized bus known as a Medical Evacuation Transport Unit (METU), caries infected patients on stretchers and benches between hospitals. (Photo by John Moore/Getty Images)

The images were taken off the coast of Tonga in the South Pacific. Photographer Grant Thomas said: “Through my images I aim to show off the amazing life we have on our planet in hope of inspiring more people to experience it for themselves and, most importantly, care for it”. (Photo by Grant Thomas/Caters News Agency)