While the National September 11 Memorial Museum has a large collection of photographs, videos, articles, and artifacts related to the events of September 11, 2001, and February 26, 1993, Spencer Finch is the only artist who was commissioned to create a new artwork for the institution, which opened on May 15 to survivors, families of the victims, and first respondents. The museum will welcome the public beginning May 21.

Finch’s work, Trying To Remember the Color of the Sky on That September Morning, is inspired by the memorably clear, intensely blue sky of that fateful morning, reports the New York Times. The work covers most of the central wall in the museum’s subterranean exhibition space.

Though it may appear from a distance to be a stone mosaic, the piece comprises individual sheets of Fabriano Italian paper that the artist has hand-painted in different shades of blue with water colors, hung like the missing person notices that filled the city’s streets in the days and weeks following the tragedy. Each of the 2,983 squares represents one of the victims of the 2001 attacks and the 1993 World Trade Center bombing.

Finch was also commissioned to create one of the few permanent installations on the High Line, The River That Flows Both Ways, which, like the 9/11 museum piece, explores a variety of azure shades—though in that case they are informed by the far less emotionally charged hues of the Hudson River’s waters.

Today’s opening ceremony was hosted by former New York mayor Michael Bloomberg, and attended by governors Chris Christie (New Jersey) and Andrew Cuomo (New York), New York mayor Bill de Blasio, and former New York mayor Rudolph W. Giuliani and former governor George E. Pataki. In a dedication speech (available at National Journal), US President Barack Obama spoke of “the man in the red bandanna,” 24-year-old Welles Crowther, a financier and volunteer firefighter who spent his last moments tending to the injured and carrying people down the stairs in the South Tower.

Obama called on visitors to the new museum to honor the memory of those, like Crowther, who lost their lives that day, “to recall and to reflect, but above all, to reaffirm the true spirit of 9/11—love, compassion, sacrifice—and to enshrine it forever in the heart of our nation.”

Trying To Remember the Color of the Sky offers similar sentiments. It frames the large wall text “No day shall erase you from the memory of time,” a quote from Virgil’s Aeneid. “As an artist, I don’t feel like my motives are always pure,” Finch told the Times. “But I feel that they’re pretty pure here. I’m a New Yorker, and I was here that day.”