Czech fishermen sort fish during the traditional Carp haul at Lake of Dvoriste near Smrzov village, Czech Republic, 02 November 2015. Carp, the traditional Czech Christmas Eve dinner, is harvested primarly from the region of southern Bohemian lakes. (Photo by Filip Singer/EPA)

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)

A participant plays a game on her phone as others watch during a break in a traditional Chinese opera competition at the National Academy of Chinese Theatre Arts in Beijing, China, November 26, 2016. (Photo by Thomas Peter/Reuters)

A fisherman carries a silver carp during a traditional fish haul at the Horusicky pond near the town of Veseli nad Luznici, Czech Republic, Tuesday, October 24, 2017. Each autumn, Czech fishermen get to serious business of a century-long tradition of catching carp for Christmas markets. Southern Bohemia, where the Horusicky pond is located, with its elaborate network of ponds is at the center of the local carp universe. (Photo by Petr David Josek/AP Photo)

A participant falls on vintage skis during a traditional historical ski race in the northern Bohemian town of Smrzovka February 21, 2015. (Photo by David W. Cerny/Reuters)

In northwest Russia, in a small village called Alekhovshchina, Nadia Sablin's aunts spend the warmer months together in the family home and live as the family has always lived, chopping wood to heat the house and making their own clothes. Sablin's book of photographs, “Aunties: The Seven Summers of Alevtina and Ludmila”, is published by Duke University Press. Here: “Two-Handed Saw, 2014”. (Photo by Nadia Sablin)

Shepherds walk with sheep through the village on their way home during autumn redyk in Gron, Tatra Mountains region of southern Poland, October 6, 2015. Redyk is a traditional, kilometres-long march of highlanders with flocks of sheep, which takes place twice a year: in the spring at the start of the grazing season, and in the autumn at season's end. (Photo by Kacper Pempel/Reuters)

A participant wearing a tiger mask performs during the “Paseo del Pendon”, a traditional artistic march in Chilpancingo, December 21, 2014. The “Paseo del Pendon” (walk banner) is a traditional celebration in the streets of Chilpancingo to mark the begin of the the year-end festivities in the city. (Photo by Jorge Dan Lopez/Reuters)