Sandy Hook, Columbine High School and Pulse nightclub share a shocking history.
On the night of June 12 2016, a gunman shot and killed 49 clubgoers in the Orlando club, injuring many more in massacre. The venue, which was built for music, dancing and celebrating with friends - now stands as a memorial site, closed and covered in flowers, balloons and photographs of those who lost their lives.
Orlando officials are still deciding on the best permanent memorial for those killed in the nightclub shooting - which was the deadliest in modern American history.
This month, almost four years after the shooting at Sandy Hook in December 2012, the new $AU66 million (NZ$69 million) educational facility will be reopened on the same site that 20 first-graders and six staff members were killed by 20-year-old Adam Lanza.
After the horror shooting, parents of children enrolled in the school in Newtown, Connecticut, couldn't image ever sending their kids back to the site.
But in an 86,000-square-foot school reconstruction, the old Sandy Hook has been replaced with buildings that contain safety features such as impact-resistant windows and state-of-the-art video monitoring.
"Our goal was to create a place of community and learning, a place that would honour those we lost and allow those who were left behind the chance to move forward," First Selectman Pat Llodra said in a statement.
But they know it will take more than a new building and returning students and staff members with special resources to cope.
COLUMBINE HIGH SCHOOL, COLORADO
On April 20, 1999, two disgruntled seniors at Columbine High School in Littleton, Colorado shot and killed 12 students and a teacher, and wounded 23 others. Eric Harris and Dylan Klebold, who committed suicide after the deadly rampage, reopened the debate on US gun control and whether tighter controls should be introduced.
After the burials of the 13 deceased, there was the issue of what to do with the school itself and the students who needed to go to class.
Spending more than $US1.2 million on repairs and renovations, officials decided to permanently close the library where many of the victims were killed. Later, it was bulldozed and turned into an atrium.
From the day of the shooting until August 16 1999, the school had its American flag at half-mast. It took four months for students and teachers to return to the school after the massacre.
Before class began on the Monday, principal Frank DeAngelis lead the 2000 students, teachers and staff in a "take back the school" rally.
While students were looking forward to getting back into their school year - some were obviously nervous about going back to the site that now had so many horrific memories.
"I'm really excited to get our school back," Julie McGinley, who was 15 when she returned to school, told the Guardian in 1999.
"But I'm nervous, too. All summer I've been trying to live life as normal. Being back there is going to trigger a lot of memories."
A permanent memorial "to honour and remember the victims of the April 20, 1999 shootings at Columbine High School" was dedicated on September 21, 2007, in Clement Park, a meadow adjacent to the school where impromptu memorials were held in the days following the shooting. The memorial fund raised $1.5 million in donations in the eight years it took to plan and create.
AURORA CINEMA, COLORADO:
On July 20, 2012, 12 people were killed and a further 70 injured after being gunned down by James Eagan Holmes as they watched The Dark Night Rises in a cinema in Aurora, Colorado.
The gunman, who confessed to the shooting but pleaded not guilty by reason of insanity, was convicted of 24 counts of first-degree murder, 140 counts of attempted first-degree murder and one count of possessing explosives. On 26th August, 2015, he was given 12 life sentences.
Six months after the shooting, the owner of the cinema decided to renovate the facility and reopen under a new name, Century Aurora. At the time of opening, many people were not supportive - particularly the victims' families.
Family members of nine of the victims wrote a letter criticising Cinemark for showing "ZERO compassion to the families of the victims whose loved ones were killed in their theatre".
But officials said that a public vote indicated they were widely in favour of reopening the cinema under a new name.
CHARLESTON CHURCH, SOUTH CAROLINA:
It has been just over a year since nine African-American churchgoers were shot dead by a young, white man who entered their Charleston, South Carolina, church, joined their Bible study for an hour and then opened fire. The shooter, Dylann Roof, blamed his victims because of their skin colour and was charged with 33 federal offences, allegedly telling investigators he wanted to start a race war.
In the wake of the shooting, security was increased at the complex with cameras and in some cases, posting armed ushers but the doors reopened.
The Confederate flag came down for good from its pole on the Statehouse grounds. The city of Charleston engraved the names of the dead on libraries and schools, and artists honoured them in portraits and murals. The church, known as Emanuel AME, was nominated for a Nobel Peace Prize.
On the one year anniversary of the mass shooting, the church held several services and events in memory of the nine victims. The memorial day, which was held on June 17 2016, had worship services, a community supper and a unity event, which were open to the public.
South Carolina Governor Nikki Haley praised the resilience of the three people wounded by and the families of the those killed.
"For them, it feels like it does to me," she said. "I feel like this just happened yesterday."
Ahead of the main memorial, more than 150 people gathered for the same Bible study where the shooting occurred last year. This time, it was led by Rev. Anthony Thompson, whose wife, Myra Thompson, died at the church shooting.
Despite the horror of what happened in June last year, the church continues to function as normal today.