Thomas M. Messer succeeded Sweeney as director of the museum (but not the foundation) in 1961 and stayed for 27 years, the longest tenure of any of the city's major arts institutions' directors. When Messer took over, the museum's ability to present art at all was still in doubt due to the challenges presented by continuous spiral ramp gallery that is both tilted and has curved walls. Almost immediately, in 1962, he took a risk putting on a large exhibition that combined the Guggenheim's paintings with sculptures on loan from the Hirshhorn Museum. Three-dimensional sculpture, in particular, raised "the problem of installing such a show in a museum bearing so close a resemblance to the circular geography of hell", where any vertical object appears tilted in a "drunken lurch" because the slope of the floor and the curvature of the walls could combine to produce vexing optical illusions.