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 general view of atmosphere during 2016 New York Comic Con – Day 1 on October 6, 2016 in New York City. The annual event offers pop culture fans exhibitors and displays of popular video games, movies and comic books and many people attending dress as their favorite character. (Photo by Daniel Zuchnik/Getty Images)

People line the streets as a dragon passes by during the Chinese New Year parade on January 29, 2012 in New York City. Thousands of people turned out to see the event which celebrated the Year of the Dragon. (Photo by John Moore/Getty Images)

In this Tuesday July 12, 2016 photo, an elephant is lifted by a crane in an upside down position in Lilongwe, Malawi, in the first step of an assisted migration of 500 of the threatened species. African Parks, which manages three Malawian reserves is moving the 500 elephants from Liwonde National Park, this month and next, and again next year when vehicles can maneuver on the rugged terrain during Southern Africa's dry winter. (Photo by Tsvangirayi Mukwazhi/AP Photo)

Women with their faces painted as various Hindu deities take part in a celebration a day after the first democratic constitution was announced in Kathmandu, Nepal September 21, 2015. Nepal adopted its first full democratic constitution on Sunday, a historic step for a nation that has witnessed war, a palace massacre and devastating earthquakes since a campaign to create a modern state began more than 65 years ago. (Photo by Navesh Chitrakar/Reuters)

Brooke Candy attends the VFILES show during New York Fashion Week at Barclays Center of Brooklyn on September 6, 2017 in New York City. (Photo by Roy Rochlin/Getty Images)

A fan cosplays as Aloy from Horizon Zero Dawn during the 2017 New York Comic Con, Day 4 on October 8, 2017 in New York City. (Photo by Roy Rochlin/WireImage)

They say a picture is worth a thousand words, and these striking images of 2017 are no exception. The photo highlights include incredible snapshots of the natural world as well as some awesome animal and human encounters. The vibrant gallery also shows thrill-seekers pushing themselves to the limit with breathtaking stunts captured in perfect clarity. The pictures have been taken by a host of photographers from around the world. Here: The two lion cubs singing their hearts out at Antelope park in Zimbabwe. (Photo by David Jenkins/Caters News Agency)