Swiss police officers stand beside of mock gates of the NEAT Gotthard Base Tunnel inside the event hall for the upcoming opening ceremony near the town of Erstfeld, Switzerland May 31, 2016. The celebrations of the opening of the Gotthard Base Tunnel will start on June 1, 2016. With a length of 57 km (35 miles) crossing the Alps, the Gotthard Base tunnel is the world's longest train tunnel. (Photo by Arnd Wiegmann/Reuters)

Vladimir Putin looks at a model of the Tupolev TU-160 bomber, or Blackjack, that was presented to him on his arrival in Olenegorsk, Russia, August 16, 2005. Putin flew in the Tupolev TU-160 bomber and took part in the launch of cruise missiles in the Arctic north. (Photo by Reuters/ITAR-TASS/Presidential Press Service)

Local residents crowd a swimming pool during a hot weather in Suining, Sichuan province, 27 July 2008. (Photo by Reuters/Stringer)

Indian children help to push an auto rickshaw along a flooded street after heavy rain in Jalandhar on June 29, 2017, as the monsoon season begins. (Photo by Shammi Mehra/AFP Photo)

A worker unloads fish from a taxi boot at a fish market in Kolkata, India on February 5, 2018. (Photo by Rupak De Chowdhuri/Reuters)

A golden lion tamarin monkey holds its newly born baby at a zoo in Jerusalem, Thursday, March 22, 2018. Golden lion tamarins are among the rarest animals in the world, according to the World Wildlife Fund. It is listed as endangered according to the International Union for Conservation of Nature. (Photo by Sebastian Scheiner/AP Photo)

Performers wearing traditional outfits from Gujarat state perform during a press preview of tableaux participating in the forthcoming Republic Day parade in New Delhi on January 22, 2020. (Photo by Prakash Singh/AFP Photo)

An Indian sadhu (Hindu holy man) sits on the banks of Sangam – the confluence of the Ganges, Yamuna and mythical Saraswati rivers – on the auspicious bathing day of 'Maghi Purnima' during the Kumbh Mela festival in Allahabad on February 19, 2019. Millions of Hindu pilgrims took the plunge in holy rivers on the most auspicious bathing days of the Kumbh Mela festival, led by naked, ash-smeared holy men and accompanied by chants from Hindu holy texts. (Photo by Sanjay Kanojia/AFP Photo)