The Washington Monument suffered significant structural damage on August 23, 2011, following a rare 5.8 magnitude earthquake centered in Mineral, Virginia. The seismic activity caused more than 150 cracks throughout the 555-foot stone obelisk, with the most severe damage occurring at the very top, known as the pyramidion. Large chunks of mortar and stone were shaken loose, and rainwater began leaking into the interior. The monument was immediately closed to the public for an extensive $15 million restoration project that involved engineers rappelling down the sides of the structure to hand-seal cracks with epoxy and replace damaged stone. It famously sat encased in a decorative "scrim" and scaffolding for years before finally reopening to visitors in May 2014. While smaller incidents have occurred, such as elevator malfunctions or minor lightning strikes, the 2011 "break" remains the most serious structural threat the monument has faced since its completion in 1884.