A mother bear takes a dip in the water to cool off in the warm summer sun but refuses to leave her three youngsters behind – so they climb aboard her back. (Photo by Jon Langeland/Solent News & Photo Agency)

A wide-angle view shows the ascent of the shuttle Challenger on January 28, 1986. In the seconds after ignition, the rocket engines' hot blast began the process of destruction. (Photo by NASA)

An ice swimming enthusiast dressed as Neptune takes to the frigid waters of Orankesee lake during the 27th annual "Winter Swimming in Berlin" on January 8, 2011 in Berlin, Germany. A local swimmers' group called the “Berlin Seals” invite ice swimmers from across Germany and abroad to the annual event. Members claim ice swimming is good for the body's blood circulation. (Photo by Sean Gallup)

Sunrise over a moor viewed from Littaford Tor, Dartmoor, UK, 2016. Autumn visits the windswept moors and granite tors of Dartmoor earlier than the rest of the south-west. While there aren’t many trees here, autumn shades appear in golden ferns and tan heather. Littaford Tors, near Two Bridges and a mile from Princetown, is a short walk and can be combined with a visit to the adjacent Wistman’s Wood. (Photo by Stuart Holmes)

British underwater photographer of the year 2021, British waters wide angle category winner and My Backyard category winner. While You Sleep by Mark Kirkland (United Kingdom), common frog taken in Malls Mire, Glasgow, Scotland. (Photo by Mark Kirkland/Underwater Photographer of the Year 2021)

A woman wearing a face mask rides a bicycle with a child, following an outbreak of the coronavirus disease (COVID-19) in Wuhan, Hubei province, China on February 8, 2021. (Photo by Aly Song/Reuters)

Farmers play tug of war in a paddy field on National Paddy Day in Tokha village, on the outskirt of capital Kathmandu, Nepal, 29 June 2021. Nepal is celebrating National Paddy Day with various events on 29 June. On this day, known as Asar Pandra, farmers begin the annual rice planting season and mark the day with various festivities such as preparing rice meals with muddy water, mud being a symbol for a prosperous season. Sixty percent of Nepal's agriculture industry relies on monsoon rain while 40 percent is carried out through irrigation. Agriculture is a major contributor to the country's GDP. (Photo by Narendra Shrestha/EPA/EFE)

The Rossiya (Russia) brig sails along the Neva River during a dress rehearsal of the 2021 Scarlet Sails Festival for school leavers in St Petersburg, Russia on June 25, 2021. (Photo by Peter Kovalev/TASS)