In 2016, the San Francisco Museum of Modern Art commissioned Mehretu to create a diptych, with each massive painting flanking the staircase in the atrium which is accessible and free to the public. "HOWL, eon (I, II)" was first exhibited to the public on September 2, 2017, and the SFMOMA plans to display the paintings for at least three years.  Each canvas is 27 x 32 feet and considered one of the largest contemporary art pieces. To facilitate the creation of the scale of the diptych, Mehretu used a decommissioned church in Harlem as her studio to create. Throughout the creation of her piece, she collaborated with jazz pianist Jason Moran. "HOWL, eon (I, II)" is a political commentary on the history of the western United States' landscape, including the San Francisco Bay Area. The foundation of each work contains digitally abstracted photos from recent race riots, street protests, and nineteenth-century images of the American west.