Mud Day Queen Riley Tulgetske, left, embraces Mud Day King Phoenix Crowder during Mud Day at the Nankin Mills Park, Tuesday, July 9, 2019, in Westland, Mich. The annual day is for kids 12 years old and younger. While parents might be welcome, this isn't an event meant for teens or adults. It's all about the kids having some good, unclean fun during their summer break and is sponsored by the Wayne County Parks. (Photo by Carlos Osorio/AP Photo)

An Indian Royal Bengal tiger looks on at an enclosure on World Tiger Day at Alipore Zoo, Kolkata, India, 29 July 2019. Kolkata zoo authority added a new Tiger to the zoo for the visitors to mark the Tiger Day. Students of Kolkata are also taking part in an awareness campaign aiming to draw attention to the threats that tigers face due to habitat loss and poaching. (Photo by Piyal Adhikary/EPA/EFE)

Militia members march in formation past Tiananmen Square during the military parade marking the 70th founding anniversary of People's Republic of China, on its National Day in Beijing, China on October 1, 2019. (Photo by Thomas Peter/Reuters)

Two paddle boarders stop to watch the sunrise on a stormy morning in Sanibel, Fla., Thursday, August 15, 2019. (Photo by J. David Ake/AP Photo)

A young girl taking part in a hairdressing contest during the 5th Abilympics Russia vocational skills championship for people with disabilities, at Moscow's VDNKh exhibition centre in Moscow, Russia on November 21, 2019. The competition is aimed at ensuring social adaptation and job opportunities for people with disabilities. (Photo by Valery Sharifulin/TASS)

A duck salesman parades his stock to commuters at a busy station in Dhaka, Bangladesh on May 23, 2018. (Photo by Nazmul Hasan Khan/Caters News Agency)

A tufted puffin is seen in Kamchatka Territory, Russia on July 17, 2018. (Photo by Yuri Smityuk/TASS)

This undated photo provided by NOAA in May 2018 shows aurora australis near the South Pole Atmospheric Research Observatory in Antarctica. When a hole in the ozone formed over Antarctica, countries around the world in 1987 agreed to phase out several types of ozone-depleting chemicals called chlorofluorocarbons (CFCs). Production was banned, emissions fell and the hole shriveled. But according to a study released on Wednesday, May 16, 2018, scientists say since 2013, there’s more of a banned CFC going into the atmosphere. (Photo by Patrick Cullis/NOAA via AP Photo)