LOWER WATERS. By using water and light as key elements of the design and by bringing people directly to the site of the attacks, we hope that visitors will remember not only the loss of life but also the sanctity of life that we live each day. The memorial space of the North Tower is clad in black granite - solemn, strong, stable - a reference to living memory and to the foundation of the towers. The private area for families of the victims and the intimate area for the public are made of thick walls of earth, to suggest comfort and stability at the depths. The fašade of the Museum of September 11 in the South Tower Footprint is stacked glass with sanded edges referring to both the construction and collapse of the towers. (Waterfall in North tower memorial area.)