The monument stands tall according to the National Geodetic Survey ( measured 2013 – 14 ) or tall according to the National Park Service ( measured 1884 ) . In 1975 , a ramp covered two steps at the entrance to the monument , so the ground next to the ramp was raised to match its height , reducing the remaining height to the monument 's apex . It is both the world 's tallest predominantly stone structure and the world 's tallest obelisk . It is the tallest monumental column in the world if all are measured above their pedestrian entrances , but two are taller when measured above ground , though they are neither all stone nor true obelisks . The tallest masonry structure in the world is the brick Anaconda Smelter Stack in Montana at tall . But this includes a non-masonry concrete foundation , leaving the stack 's brick chimney at tall , only about taller than the monument 's 2015 height . If the monument 's aluminum apex is also discounted , then the stack 's masonry portion is taller than the monument 's masonry portion . In 2001 , a temporary visitor security screening center was added to the east entrance of the Washington Monument in the wake of the September 11 attacks . The one-story facility was designed to reduce the ability of a terrorist attack on the interior of the monument , or an attempt to seize and hold it . Visitors obtained their timed-entry tickets from the Monument Lodge east of the memorial , and passed through metal detectors and bomb-sniffing sensors prior to entering the monument . After exiting the monument , they passed through a turnstile to prevent them from re-entering . This facility , a one-story cube of wood around a metal frame , was intended to be temporary until a new screening facility could be designed
September 11 attacks
September 11 attacks
Washington Monument