It is hard to believe that it has been 15 years since the day that came to change the world - September 11th 2001, when the Twin Towers of the World Trade Center, once the tallest buildings in the world, designed by the American architect Minoru Yamasaki in 1965 and completed in 1973, were destroyed to the ground. In their footprint, the most magical Memorial was built, designed by Israeli-American architect Michael Arad. His design was chosen from over 5,700 entries, the largest competition in the history of architecture, and it consists of straightforward, deeply embedded squares, a timeless echo of loss, and the void that remains. Waterfalls cascade into shimmering pools, ringed by bronze parapets bearing the names of the 2983 victims. At night, the names are illuminated from within. The twin fountains are surrounded by hundreds of trees on a serene plaza at street level, landscaped by Peter Walker & Partners, the perfect day to visit 9/11 Memorial. And to remember.