World's Greatest Swimming Pools: Four Seasons, Serengeti Pool, Tanzania. A show of elephants, buffalo and baboons awaits thanks to an active watering hole below the free-form infinity pool at this plush hideaway inside Serengeti National Park. Bonus: Because of infrared technology at the hole, guests can be notified on their bedroom TV when animals are approaching. When you've got word of wildlife on the horizon, catch them from your private terrace – or head back to the pool. (From $1,650). (Photo by Four Seasons)

An Indian priest worships six-year-old Hindu girl Anushka Chetterjee dressed as the Hindu goddess Durga at a “pandal” for the celebrations of the “Durga Puja” festival in Kolkata on September 28, 2017. The five-day Durga Puja festival, which commemorates the slaying of the demon king Mahishasur by the goddess Durga, marks the triumph of good over evil. (Photo by Dibyangshu Sarkar/AFP Photo)

Hospitality staff members laugh as they stand on Tiananmen Square before the closing ceremony of China's 19th Party Congress at the Great Hall of the People in Beijing, Tuesday, October 24, 2017. The ruling Communist Party on Tuesday formally lifted Xi Jinping's status to China's most powerful ruler in decades, setting the stage for the authoritarian leader to tighten his grip over the country while pursuing an increasingly muscular foreign policy and military expansion. (Photo by Mark Schiefelbein/AP Photo)

A woman wearing leggings with the colours of the US flag walks along a street of Havana on February 18, 2015. President Barack Obama announced Thursday he will make a landmark visit to Cuba on March 21-22, pledging to address human rights as America pursues a historic thaw with its former Cold War foe. (Photo by Yamil Lage/AFP Photo)

Rescue workers try to help a driver out of his car, after the vehicle was stuck over an alley in Wenzhou, Zhejiang province, August 4, 2014. The car rolled off the edge of a road after the driver was late to brake, according to local media. (Photo by Reuters/Stringer)

Typhoon Bopha moves toward the Philippines, observed from the ISS, on December 2, 2012. (Photo by AP Photo/NASA via The Atlantic)

The President of the sushi restaurant chain Sushi Zanmai, Kiyoshi Kimura, cuts a blue fin tuna outside his main restaurant at the outer Tsukiji market in Tokyo January 5, 2015. The 180 kg blue fin tuna traded at a price of 4.5 million yen (37,500 USD) and was the most expensive fish at this year's New Year auction at the Tsukiji market, local media reported. (Photo by Thomas Peter/Reuters)

People leave a giant air purifier, which its inventor calls a “super tree”, in Lima's district of Jesus Maria November 24, 2014. In Peru's notoriously polluted capital Lima, local inventor Jorge Gutierrez, a retired naval engineer, is deploying the giant air purifiers that double as billboards to suck up carbon dioxide and dangerous levels of smog. (Photo by Mariana Bazo/Reuters)