The front wheels of a tractor lift off the ground as the driver moves a heavy trailer outside Peshawar, Pakistan February 19, 2018. (Photo by Fayaz Aziz/Reuters)

Two white storks stand close to each other on their nest on a tree in Zerbolo, Italy, Thursday, October 26, 2017. (Photo by Antonio Calanni/AP Photo)

A pine marten – one of a few wild mammals doing well in Britain (although they number just 3,700). A fifth of the country’s wild mammals are at high risk of extinction, research shows. (Photo by Maurice Flynn/The Mammal Society)

Women are reflected in a puddle as they walk across Red Square in Moscow, Russia on April 26, 2018. (Photo by Yuri Kadobnov/AFP Photo)

A dog jumps into the air to catch a ball along the beach near the County Kerry village of Rossbeigh, Ireland, February 4, 2018. (Photo by Clodagh Kilcoyne/Reuters)

European bisons (also known as Wisent) at the Bison farm in Muczne, southeastern Poland, 30 December 2018. The Bison farm is a continuation of bison breeding in Bieszczady, which was started in 1963. Here visitors can admire the bison of Bialowieza-Caucasian line, also called the mountain race. The European Bison is the national animal of Poland. (Photo by Darek Delmanowicz/EPA/EFE)

Passengers wait for a train to depart from the Hankou Railway Station in Wuhan, central China's Hubei province, Friday January 13, 2017. Officials expect that Chinese travelers will make almost 3 billion trips during the holiday travel rush that starts runs through Feb. 21. These trips include intercity flights, trains and local bus rides to villages for China's 1.4 billion people. (Photo by Chinatopix via AP Photo)

Steam emerges from a cooling tower of the nuclear power plant Leibstadt near Leibstadt, Switzerland, November 18, 2014. (Photo by Arnd Wiegmann/Reuters)