Reuters photographers witnessed the biggest stories of 2017 - from Donald Trump's first year as U.S. president to the flight of Rohingya refugees from Myanmar, from Venezuela's crisis to the fall of Islamic State and a tower block inferno in London.
This feature presents some of their strongest images.
It also gives the photographers a chance to tell the stories behind their pictures and explain in their own words how the images were taken.
Through it all, the photographers raise a question that shows how close they were to the action: in moments of crisis, should they take pictures or try to help?
Toby Melville: "I was on the footpath below the southeast end of Westminster bridge, shooting pictures for the on-going Brexit story. I saw in my peripheral vision a large dark shape around 3-5 metres away come over the parapet and hit the ground approximately 10 metres below.
I thought it was a terrible but isolated accident. I immediately called for an ambulance and ran to the top of the steps to try to get help at St Thomas's, the nearby hospital. While on the phone, I saw a couple more people lying on the pavement amongst debris, covered in blood or unconscious.
There were other people scattered along the bridge and pavement in various states of injury and distress. I realised this was not an accident but something premeditated. As the emergency services were on the scene now, I started taking photos along the bridge.
I was unsure if danger was still present. I didn't know a car had been driven into these people. I hadn't heard any screams, loud engine noises or the gunshots of the armed police shooting and killing the perpetrator of the attack, Khalid Masood. I thought the injured or dead might also have been shot and a gunman might still be on the loose.
Armed police arrived and cleared the bridge. I called the office and started filing photographs from the back of the camera, transmitting most of the frames I had shot for the office to choose, edit and crop. A week later I walked back over the bridge, everything was 'back to normal', in a way.
But the sight of the first victim falling and the sickening thud as he hit the pavement still goes through my mind. I wonder whether I should have transmitted all the frames I shot. The sequence of pictures is hard to look at. I remind myself I was lucky. I had walked over the bridge about a minute before the attack. Others weren't so fortunate."