The National September 11 Memorial and Museum at the World Trade Center site, is a tribute to the nearly 3,000 people killed in the terrorist attacks of September 11, 2001. Featuring twin reflecting pools within the footprint where the Twin Towers once stood, it is hoped that the memorial will serve as a record of those lost.
Sadly, it is not the only memorial of atrocities committed around the world.
1. Choeung Ek, Cambodia
Better known as the 'Killing Fields', this mass grave south of the Cambodian capital, Phnom Penh, is where the Khmer Rouge killed up to 17,000 people in the 1970s. The centrepiece is a Buddhist stupa, made with transparent acrylic, holding 8,000 human skulls.
2. Memorial to the Victims of Communism, Czech Republic
Set in the centre of Prague, this memorial features seven bronze figures descending a flight of stairs, each appearing more decayed than the last. It is symbolic of the dehumanizing toll of four decades of Communist rule, a bronze strip in the stairs giving the grim numbers.
3. Memorial to the Murdered Jews of Europe, Germany
This gently sloping, 4.7-acre swathe of land in Berlin near the Brandenburg Gate memorialises the horrors of the Holocaust. Visitors walk through a sobering thicket of 2,711 concrete blocks that rise up to 16ft high.
4. House of Slaves, Senegal
The Dutch-built slave quarters on Gorée Island, a UNESCO World Heritage site, are both memorial and museum: a stark reminder of the countless Africans sold into slavery near here from 1536 to 1848. The Door of No Return is particularly poignant.
5. Halabja Monument and Peace Museum, Kurdistan, Iraq
On 16 March 1988, Chemical Ali blitzed the small town of Halabja with chemical weapons as part of his crusade to "wipe out the Kurds." The moving museum has photos and reconstructions from the day and its aftermath, and the guides are locals who survived the attack. A few miles away is the Halabja Memorial Cemetery where many of the 5,000 victims are buried.
Wanderlust's Lyn Hughes visited the museum, on her trip to Iraq.
6. Auschwitz, Poland
A Nazi concentration and extermination camp, Auschwitz has become the dominant symbol of the Holocaust.
From the spring of 1942 it was the largest site for the murder of Jews brought here under the Nazi plan for their extermination, with more than 1,100,000 men, women, and children losing their lives here.
7. Hiroshima Peace Memorial Park, Japan
Dominated by the A-Bomb Dome, the skeletal remains of the former Industrial Promotion Hall, this memorial park in the centre of Hiroshima. It is dedicated to the legacy of Hiroshima as the first city in the world to suffer a nuclear attack, and to the memories of the bomb's direct and indirect victims.
8. Kigali Genocide Memorial Centre
The Kigali Genocide Memorial Centre, in Kigali, Rwanda, commemorates the Rwandan genocide in 1994. It is built on the site where up to 250,000 genocide victims were buried in mass graves. The centre includes three permanent exhibitions and acts as a permanent memorial to victims, and a place for people to grieve those they lost.
READ MORE: myWanderlust contributors share their experiences visiting memorials around the world