A resident removes mud on a street brought by monsoon rains in San Mateo, Rizal, Philippines, August 14, 2016. (Photo by Erik De Castro/Reuters)

A mouse rides on the back of a frog in floodwaters in the northern Indian city Lucknow June 30, 2006. (Photo by Pawan Kumar/Reuters)

Sumo wrestler Kaiho eats a “chanko” meal in Nagoya, Japan on July 18, 2017. After ending practice at 10:30 a.m., the wrestlers mingle with fans, sign autographs and pose for photos before the first of their two daily meals. (Photo by Issei Kato/Reuters)

Gas-masked men of the British Machine Gun Corps with a Vickers machine gun during the first battle of the Somme, 1916. (Photo by General Photographic Agency/Getty Images)

Many of the 12 million people who entered the US through New York’s Ellis Island wore traditional dress from their homelands. Here: A Ruthenian woman circa 1906 from the region historically inhabiting the kingdom of the Rus, incorporating parts of modern-day Slavic speaking countries. Her outfit consists of a shirt and underskirt made from linen embroidered with traditional floral-based patterns. (Photo by Augustus Francis Sherman/New York Public Library/The Guardian)

Young cheetahs eat meat at The Cheetah Conservation Fund (CCF) center in Otjiwarongo, Namibia, on August 13, 2013. The CCF started breeding Anatolian livestock dogs to promote cheetah-friendly farming after some 10,000 big cats – the current total worldwide population – were killed or moved off farms in the 1980s. Up to 1,000 cheetahs were being killed a year, mostly by farmers who saw them as livestock killers. But the use of dogs has slashed losses for sheep and goat farmers and led to less retaliation against the vulnerable cheetah. (Photo by Jennifer Bruce/AFP Photo)

A man carries a bag on his back in Guangzhou, Guangdong province, January 26, 2016. According to traffic police, over 2.9 billion trips will be made around China during the 40-day Spring Festival travel rush, which started on January 24. (Photo by Reuters/Stringer)

A 20 metre high spiral staircase in a tower used as an emergency exit, is seen inside a Federal Reserve bank (Bundesbank) bunker, prior to the bunker's official opening to the public in Cochem, Germany, March 18, 2016. West Germany's Central Bank (Deutsche Bundesbank) stored some 20 billion German marks of emergency notes in two underground bunkers, one in Frankfurt the other in Cochem, between 1964-1988 during the cold war. (Photo by Kai Pfaffenbach/Reuters)