The Rio de Janeiro Olympics kick off on August 5 for some two weeks of competitive games drawing athletes as well as audiences from around the world. As they prepare to cover the event, Reuters photographers look back on their favourite pictures from past Olympics where they captured the action on the ground as well as the participants' tears and joy that followed. (Photo by Lucy Nicholson/Reuters)

Serbian police officers of the Special Anti-Terrorist Unit pose for a picture in their base outside Belgrade October 8, 2014. When the killing of an unarmed black teenager by a white policeman in Ferguson, Missouri, in August sparked sometimes violent protests, the response of police in camouflage gear and armoured vehicles wielding stun grenades and assault rifles seemed more like a combat operation than a public order measure. Some U.S. police departments have recently acquired U.S. military-surplus hardware from wars abroad, but there are many law enforcers around the world whose rules of engagement also allow the use of lethal force with relatively few restrictions. But for every regulation that gives police wide scope to use firearms, there is another code that sharply limits their use. In Serbia, police may use measures ranging from batons to special vehicles, water cannon and tear gas on groups of people who have gathered illegally and are behaving in a way that is violent or could cause violence, but they may use firearms only when life is endangered. (Photo by Marko Djurica/Reuters)

A landscape photographer turned the camera on himself to take a set of incredible selfie while visiting some of the world's most beautiful destinations. Paul Zizka, 39, from Alberta, Canada, has been a photographer for nine years, and thought that featuring in his own pictures would emphasize the nature surrounding him and create a more unique shot. Here: Lake Minnewanka, Banff National Park, Alberta, Canada. (Photo by Paul Zizka/Caters News Agency)

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)

Shoppers walk down stairs featuring a five-metre-high reproduction of Vincent van Gogh's signature painting “Sunflowers”, at the entrance to Ocean Terminal in Hong Kong July 15, 2013. A premium three-dimensional reproduction of works of Van Gogh, the RELIEVO collection, approved by the curators of the Van Gogh Museum in Amsterdam, is on display at a gallery inside Harbour City shopping mall attached to the terminal. (Photo by Bobby Yip/Reuters)

The Villarrica volcano shows signs of activity, as seen from Pucon, some 800 kilometers south of Santiago, on November 21, 2022. Villarrica volcano is among the most active in South America. (Photo by Mario Quilodran/AFP Photo)

Ornamental chicken breeding clubs have emerged in Indonesia, Thailand, North America and even European countries such as the UK and France. Malaysia is however the epicenter of this cultural phenomenon. These chickens are prized for their build, size, behavior and showmanship by their owners and competitions or beauty contests as they are often described are held almost every week in at least one village in Malaysia. Judges sit around a square table inspecting each chicken for a few minutes trying to determine a champion specimen in its own weight class based on its stance, temperament and physical assets like wings, tails and comb. The walk or strut by an ornamental chicken in a beauty contest, much like a runway model, constitutes a large part of the scoring system. (Photo by Ernest Goh/2013 Sony World Photography Awards)

Cloud inversion taken at Sunrise in Mam Tor, Derbyshire, UK on August 30, 2016. (Photo by David Zdanowicz/REX Shutterstock)