Sheep walk as they are herded to summer pastures in Serra da Estrela, near Seia, Portugal June 27, 2015. In late June, shepherds young and old in the Seia region of central Portugal start guiding sheep, goats and cattle to the Serra da Estrela, the country’s highest mountains, in search of better pastures. There they stay until the end of September. Modern-day shepherds may have mobile phones to keep in touch with family and friends, but their lifestyle has changed little for centuries. The sound of cowbells and the bark of longhaired mastiffs starts early in the morning as the animals – often decorated with traditional woollen balls on their horns – are herded up steep, narrow paths. (Photo by Rafael Marchante/Reuters)

M42 Subtle V1 cropped. One of the most well-known astronomical objects in our universe is the Orion Nebula and this image depicts the wider region of the Orion Molecular Cloud Complex that is its home. This complex also includes another popular target for astrophotographers, the Horsehead Nebula, as well as Barnard’s Loop and the Running Man Nebula, which can be seen to the left of this photograph. (Photo by Patrick Gilliland)

Participants run through the streets of the Back Bay during the 16th annual Santa Speedo Run in Boston, Massachusetts, December 12, 2015. (Photo by Brian Snyder/Reuters)

Egmont National Park in New Zealand with Mt. Taranaki at its center is seen in a Landsat 8 satellite image taken July 3, 2014 and released by NASA November 14, 2014. The image is from the book “Sanctuary: Exploring the World's Protected Areas from Space”, published by the Institute for Global Environmental Strategies with support from NASA, which was released this week. (Photo by Reuters/NASA/USGS)

This aerial picture taken on August 16, 2020, shows the MV Wakashio bulk carrier that had run aground and broke into two parts near Blue Bay Marine Park, Mauritius. A ship that has leaked more than 1,000 tonnes of oil in pristine waters off the Mauritius coast has split into two, its Japanese operator said August 16, 2020. (Photo by AFP Photo/Stringer)

Giant panda Ying Ying rests on a rock in its enclosure while a visitor takes a selfie at Ocean Park in Hong Kong, China, 24 September 2020. An An turned 35 in August. Giant pandas in the wild can live up to 20 years on average, while lifespans of those under human care can reach over 30 years. (Photo by Jerome Favre/EPA/EFE)

A mannequin wearing a face mask and nurse's uniform stands next to a sign supporting the NHS, stands in a field during the Covid-19 pandemic on October 06, 2020 in Northwich, United Kingdom. (Photo by Christopher Furlong/Getty Images)

The Soyuz MS-17 spacecraft carrying the International Space Station (ISS) expedition 64 crew of NASA astronaut Kate Rubins and Russian cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov blasts off to the ISS from the Russian-leased Baikonur cosmodrome in Kazakhstan on October 14, 2020. (Photo by Roscosmos/Handout via AFP Photo)