One World Trade Center, more simply known as 1
WTC and previously known as the Freedom Tower, is the lead
building of the new World Trade Center complex in Lower
Manhattan, New York City.
We will never forget September 11, 2001.
Along with the protection offered by the reinforced concrete
base, a number of other safety features were included in the
building's design, in order to better prepare it for a major
accident or terrorist attack. These features include
3-foot (91 cm) thick reinforced concrete walls for all
stairwells, elevator shafts, risers, and sprinkler systems;
extra-wide, pressurized stairwells; a dedicated set of
stairwells exclusively for the use of firefighters; and
biological and chemical filters throughout its ventilation
It's expected completion is in 2013.