Demonstrators clash with members of the Bolivarian National Police as protests continue in Caracas, Venezuela, 20 April 2017. The Bolivarian National Guard, using tear gas, tried to disperse protests against the government of Venezuelan President Nicolas Maduro. (Photo by Miguel Gutierrez/EPA)

Small transportation boats, known as bumboats, leave trails of light as they travel across Marina Bay past the skyline of Singapore in this photo taken in 2004. Singapore holds a Jubilee weekend from 7 to 10 August to celebrate the 50th anniversary of its independence. Fifty years ago, hundreds of small boats lined the Singapore river in the city centre. Today, most small boats are gone, except a handful of neon-lit tourist ferries. Maritime trade is still the backbone of the city-state but after decades of rapid growth Singapore, which at less than half the size of London is among the world’s most densely populated nations, is also a popular tourist destination and a thriving global financial hub. (Photo by Edgar Su/Reuters)

Yak near Yamdrok lake, Tibet. It is a long-haired bovinae found throughout the Himalayan region of south Central Asia, the Tibetan Plateau and as far north as Mongolia and Russia. The Tibetan economy is dominated by subsistence agriculture. Due to limited arable land, the primary occupation of the Tibetan Plateau is raising livestock, such as sheep, cattle, goats, camels, yaks, dzo, and horses. The Tibetan yak is an integral part of Tibetan life. (Photo by Dennis Jarvis)

Camels graze in front of a spacecraft tracking station ahead of the Soyuz MS-10 upcoming launch at the Baikonur Cosmodrome, Kazakhstan, October 9, 2018. (Photo by Shamil Zhumatov/Reuters)

Sailors from the Indonesian Navy carry a victim of a boat sinking last week off the coast of Indonesia, on December 21, 2011 in Banyuwangi, East Java, Indonesia. (Photo by Ulet Ifansasti/Getty Images)

Puppies, pugs and the perfect antidote to political pandemonium, it’s the Kennel Club’s dog photographer of the year competition. Here: Jamie Morgan’s two Afghan hounds won first place in the portrait category. (Photo by Jamie Morgan/PA Wire)

German police officers take pictures as fireworks explode next to the Quadriga sculpture atop the Brandenburg gate during New Year celebrations in Berlin, Germany, January 1, 2017. (Photo by Fabrizio Bensch/Reuters)

Stingray City is a series of shallow sandbars found in the North Sound of Grand Cayman, Cayman Islands. It is a tourist attraction, where southern stingrays are found in abundance and visitors can pet and interact with the animals.