On September 11th 2001, the New York City skyline was changed forever when hijacked airplanes were deliberately crashed into the Twin Towers of the World Trade Center by terrorists.
In four separate but connected incidents on that fateful morning, almost 3,000 people were killed; 2,753 in New York, 184 at the Pentagon and 40 in Pennsylvania.
After an initial period of grief and horror, city officials were eager to regenerate the devastated part of Lower Manhattan and a new complex of buildings now stands in the footprint of the old World Trade Center.
Guests at New York hotels can visit the 9/11 Memorial within this new space, a moving tribute to those killed in the atrocity that includes two large pools of remembrance inscribed with every victim's name.
There will also be the chance to glimpse the nearby One World Trade Center, now the tallest building in the Western Hemisphere.
It is well worth adding a visit to this somber, moving memorial site to any New York City trip itinerary. Visitors will need to request a free pass from the 9/11 Memorial website, which can be exchanged for entry at a designated time on the day.