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)

The lightest material ever made has been produced by a team of scientists in China, a Chinese university announced.

A little blue penguin which was found at Papamoa Beach, covered in oil after the Liberian cargo ship, Rena, hit a reef, on October 7, 2011, in Tauranga, New Zealand. Reports of an oil sheen have been spotted on the surface of the water surrounding the ship and two penguins have been found covered in oil. (Photo by SUNLIVE New Zealand/Getty Images)

A person dressed up as Damien Lavey of Monster Prom attends the 2019 New York Comic Con in New York City, New York, U.S., October 3, 2019. (Photo by Shannon Stapleton/Reuters)

Miss USA 2012 Nana Meriwether crowns Miss Connecticut USA Erin Brady the new Miss USA during the 2013 Miss USA pageant at PH Live at Planet Hollywood Resort & Casino on June 16, 2013 in Las Vegas, Nevada. (Photo by Ethan Miller)

Historical reenactor Troy Kotz poses with a mug of wassail in the parlor of the Guyon-Lake-Tysen House during the annual Candlelight Tour of Historic Richmond Town, Saturday, December 13, 2014, in the Staten Island borough of New York. The annual event lets visitors experience an authentic Victorian Christmas. This image was made using the TinType by Hipstamatic iPhone app. (Photo by Chad Rachman/New York Post)

A participant covers himself with a blanket as it rains at the venue of the World Culture Festival on the banks of a river in New Delhi, India, March 11, 2016. (Photo by Adnan Abidi/Reuters)