In the 1990s, Neustein returned to large-scale installation, with a series of environmental works he called the "Five Ash Cities". He worked closely with Wendy Shafir, who was alternately his dealer, curator, and collaborator. The "Ash Cities" were immersive, room-sized relief maps of cities, constructed out of packed ashes that rested on the floor of the exhibition space. They often included crystal chandeliers installed to hang low to the ground, so they nearly touched the ash-covered floor. "Ash Cities" were realized at Southeastern Center for Contemporary Art, North Carolina; the Ujazdów Castle, Warsaw; moCa, Cleveland, curated by Jill Snyder; "Bilder Sind Verboten" at Martin Gropius-bau, Berlin, curated by Eckhart Gillen and Amnon Barzel; and the Herzliya Museum, curated by Wendy Shafir. In 1990, another chandelier work, "How History Became Geography" was exhibited at the Barbican Centre, London. Documentation was later shown by the Israel Museum.