The Tower of Voices is a monumental 93-foot-tall structure located at the entrance of the Flight 93 National Memorial in Shanksville, Pennsylvania. Completed in 2018, it serves as a "living" memorial to the 40 passengers and crew members who lost their lives on September 11, 2001. The tower contains 40 wind chimes, each uniquely tuned to represent a distinct voice from the group. The chimes are made of polished aluminum and range in length from 5 to 10 feet; they are designed to be played naturally by the wind as it passes through the tower's hollow core. The structure itself is a "precast concrete" masterpiece, featuring a series of C-shaped fins that create a "sound chamber" effect. Its height was specifically chosen so that it would be the first thing visitors see as they approach the memorial. In 2026, it remains one of the most poignant sound-based memorials in the world, intended to provide a "serene and discordant" acoustic experience that changes every day based on the wind speed and direction, symbolizing the eternal presence of the 40 heroes.