“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)

A gun is seen next to the body of a man was killed in a shootout with police in Manila, Philippines early October 21, 2016. According to the police, sachets containing substance believed to be drug shabu (Methamphetamine Hydrochloride) were found in the killed man's pockets. (Photo by Damir Sagolj/Reuters)

A woman in yukata, casual summer kimono, poses for a photo at Fushimi Inari Taisha in Kyoto, Japan on October 2, 2019. (Photo by Matthew Childs/Reuters)

Growing cities, overuse of fertilizers and factory wastewater have degraded China's water supplies to the extent that half the nation's rivers and lakes are severely polluted. China aims to spend $850 billion to improve filthy water supplies over the next decade, but even such huge outlays may do little to reverse damage caused by decades of pollution and overuse in Beijing's push for rapid economic growth. Photo: Fishermen row a boat in the algae-filled Chaohu Lake in Hefei, Anhui province, June 19, 2009. (Photo by Jianan Yu/Reuters)

Actors dressed as zombies and ghouls perform during a drive-in haunted house show by Kowagarasetai (Scare Squad), for people inside a car in order to maintain social distancing amid the spread of coronavirus, at a garage in Tokyo, Japan on July 3, 2020. (Photo by Issei Kato/Reuters)

Afghan children watch the Kabul view as they stand near to a victim's grave who lost her life in the recent attack on Sayyid al-Shuhada school in west Kabul, Afghanistan, 11 May 2021. Following a terrorist attack on a girls school in Kabul on 08 May that killed some 80 person and injured more than 100, the Afghan government declared 11 May as a national mourning day. (Photo by Hedayatullah Amid/EPA/EFE)

A mysterious sea creature with some frighteningly sharp teeth washed up on a beach in England last week, where David Mackland snapped these photos. A Grind TV story reports that Mackland estimated the creature to be about 4-5 feet in length. (Photo by David Mackland/OurCarnoustie)

A helicopter of the Food and Agriculture Organization of the United Nations (FAO) flies through millions of Locusts as spreads pesticide to fight against a swarm of locusts threatening to reach Amparihibe village on May 7, 2014 in Tsiroanomandidy, Madagascar. FAO mission is to fight the locust's swarm with an insecticide. (Photo by AFP Photo/RIJASOLO)