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)

Roped up climbers leave the summit of Breithorn at 4,164 metres (13,661 feet) on the ridge marking the border with Switzerland (left) and Italy in the Alpine resort of Zermatt August 4, 2014. Switzerland will vote on November 30 on an initiative from the group Ecopop which proposes a cap on the number of immigrants. The group says it is motivated by concerns about a lack of living space exerting too much pressure on the land and natural resources, rather than by opposition to foreigners. (Photo by Denis Balibouse/Reuters)

A person practices ski-joering at the Avoriaz resort in the French Alps on February 11, 2021. (Photo by Jeff Pachoud/AFP Photo)

Armed police Taser a man inside the grounds of the Houses of Parliament on 11 December 2018. (Photo by Peter Nicholls/Reuters)

Gunfire erupted at a Denver pot celebration Saturday, injuring two people and scattering a crowd of thousands who had gathered for the first 4/20 counterculture holiday since the state legalized marijuana... Photo: A woman smokes a large marijuana joint at the Vancouver Art Gallery during the annual 4/20 day, which promotes the use of marijuana, in Vancouver, British Columbia April 20, 2013. (Photo by Ben Nelms/Reuters)

A New York window cleaner strapped to the side of The RCA Building in the Rockefeller Center, with St Patrick's Cathedral below him to the left. (Photo by William Lovelace/Express/Getty Images). 2nd May 1961

A young fan watches as Green Bay Packers running back AJ Dillon (28) tries his best to ride her bicycle to training camp on Monday, August 1, 2022, at Ray Nitschke Field in Green Bay, Wis. (Photo by Dan Powers/USA TODAY Sports)

“Cassowaries are large, flightless birds related to emus and (more distantly) to ostriches, rheas, and kiwis”, writes Olivia Judson in the September issue of National Geographic magazine. How large? People-size: Adult males stand well over five foot five and top 110 pounds. Females are even taller, and can weigh more than 160 pounds. Dangerous when roused, they’re shy and peaceable when left alone. But even birds this big and tough are prey to habitat loss. The dense New Guinea and Australia rain forests where they live have dwindled. Today cassowaries might number 1,500 to 2,000. And because they help shape those same forests – by moving seeds from one place to another – “if they vanish”, Judson writes, “the structure of the forest would gradually change” too. (Photo by Christian Ziegler/National Geographic)