After each massacre, survivors and witnesses have echoed the words "no more" - yet mass shootings have continued to plague the United States. In fact, shootings only have continued to increase over the past few years. The shooting at Marjory Stoneman Douglas High School in Florida is the 18th attack in a school in 2018 alone. Below are some of the worst US school shootings in the last 20 years.
Thousands of children's shoes have been kept on display outside the US Capitol as a temporary memorial to children killed by gun violence.
Here's a glimpse of all that happened around the world last month, in 14 images.
At least 50 people have been killed after a gunman opened fire at the Mandalay Bay Casino in Las Vegas - the deadliest mass shooting in the history of United States. Here's a look at other such incidents that have struck the country in recent times.