Rohingya refugee sisters Nur Kaida (R) and Ruhana hug each other at their shelter at the Palongkhali refugee camp near Cox's Bazar, Bangladesh December 21, 2017. (Photo by Marko Djurica/Reuters)

Cropped shot of a woman flirtatiously touching leg of man in a suit with her foot under the table. (Photo by LightField Studios/Skyfish Digital Media/Getty Images)

A Southwest Airlines jet takes off from Reagan National Airport with a thunderhead to the east on June 20, 2017 in Alexandria, VA. (Photo by Jonathan Newton/The Washington Post)

A Virgin Atlantic passenger plane flies in the sky with the moon seen in the background, in London, Britain January 19, 2016. (Photo by Toby Melville/Reuters)

A homeless girl asks for alms outside a coffee shop in Mumbai, India, June 24, 2016. (Photo by Danish Siddiqui/Reuters)

Smoke plumes rise from Mount Etna, one of the most active volcanoes in the world in Sicily, Italy on June 28, 2016. (Photo by Etna Walk/Rex Feature/Shutterstock)

A boy collects drinking water from a hand pump in Kutubdia, Bangladesh on March 30, 2016. Kutubdia is one of many islands affected by some of the fastest recorded sea-level rises in the world. The island has halved in size in 20 years. (Photo by SIipa/Rex Features/Shutterstock)

A volcanic eruption at Mount Etna’s Vorgaine crater in Sicily, Italy on December 3, 2015. (Photo by Marco Restivo/Barcroft Media)