1 The galleria progressiva in the Solomon R. Guggenheim Museum and the Museum of Unlimited Growth ANA LUISA_ROLIM *1 LUIZ_AMORIM *2 MARIA JÚLIA_JABORANDY*3 … (*1 UFPE; UNICAP) (*2 UFPE) (*3 UNICAP) Abstract. The Solomon R. Guggenheim Museum, designed by Frank Lloyd Wright (1943-1959) and the Museum of Unlimited Growth (1939), by Le Corbusier, are examples of the galleria progressiva, a type of architectural configuration containing sequentially uninterrupted spaces, emerged after the French Revolution, that generates specific sets of linear events and has the potential to guide the visitor’s experience relying more on the building geometry than on symbolic or guidance artifices. In Wright’s design visitors would take the elevator up and descend, on a leisure mode drift, through a fixed journey on the sloping plane, from which they would sidestep into exhibition rooms and then return to the skewed plane of the spiral gallery in the rotunda. In a similarly deterministic configuration concept, Le Corbusier designed a museum to be accessed from an atrium in the mid-point of the structure, from where visitors would take a ramp to the upper floor, occupied by galleries, laid out in a square- shaped spiral overlaid with a 4-axis cross, that could grow endlessly as more exhibiting spaces were needed. As part of a broader PhD research on visitors’ engagement in the galleria progressiva museum type, the interest of this paper relies on finding clues on the morphology of the concepts by two of the most iconic architects in the twentieth- century that might lead to their potential in facilitating engagement. To investigate morphological aspects, space syntax was used as the main theoretical ground, relying on justified graphs, convex, axial and visual analysis maps as topological representations of both spatial structures. Some of the key questions in future developments of this research are: Are both spiral-like configurations equally deterministic when it comes to route alternatives? Doe ones favor a more exploratory visit than the other? Which spatial system is easier to navigate? How does Le Corbusier’s architectural promenade concept cope with an apparently very restrictive layout? By addressing these issues, we hope to revisit two important museum designs and, at the same time, bring light on the history of museum types by examining the galleria progressiva. Keywords. Modern museums, Museum morphology, Space Syntax, Le Corbusier, Frank Lloyd Wright Introduction This paper fits within a broader PhD research, currently in progress, on museum visitors’ engagement within uninterrupted sequential spaces named galleria progressiva 1 , utilizing the social logic of space (or space syntax) and neuroscience as theoretical grounds. Using configurational analysis, two emblematic museum concepts will be specifically discussed here, the Solomon R. Guggenheim Museum (1943-59) by Frank Lloyd Wright, and the Museum of Unlimited Growth (1939) by Le Corbusier. These two cases are compared because they are examples of a thorough application of the galleria progressiva in modern architecture, that, although having distinct shapes, their spatial and formal conceptions are based on the logic of the spiral, besides having the same use as museums. In regards to previous studies 2 , specially in the space syntax field we intend to extend the discussion of some of these seminal ideas often related to criticizing the galleria progressiva for its reductionism of route possibilities 3 and restriction of spatial structure experience, which tends to leave, as in the Guggenheim, “no room for probabilistic effects of the layout over exploration and encounter.” 4 . The following questions permeate the investigation: Which of the two spatial systems discussed here is more favorable to engagement? And which configurational particularities lead to the probability of engagement? We begin by defining the galleria progressiva as a type of nineteenth-century museum organization, then, contextualize the two museum concepts according to such type, setting the basis to the analysis. Following, we present and discuss the analysis of both case studies through convex, axial and visibility maps, isovists, and justified graphs to, then, reach some conclusions.