Unlike other American megacities, São Paulo's financial and administrative center has shifted multiple times, specifically four times over the last century. These shifts have significantly affected the city's former centers. This study examines the transformation of São Paulo's original center, the Historic Triangle, where layers of urban development that rapidly overlaid in the 20th century led to the demolition of historic buildings and verticalization. The shift of centrality subsequently caused the decay of this historic center. Despite the decline in its financial and administrative importance, the Historic Triangle remained a valuable site for its architectural heritage, though its cultural landscape and imageability are at risk. The data for this study was gathered from site surveys, historical maps, and experts' opinions and was analyzed using GIS and SPSS. An original 3D video was produced to illustrate the transformation and rapid verticalization of the Historic Triangle. To address the complex architectural landscape, the existing buildings are categorized into three generations: 1stG (oldest), 2ndG (transitional), and 3rdG (newest). We examined each category's façade details, building design, and urban integration and provided recommendations for conservation measures and policies to preserve the site's historical integrity and enhance its new role as a tourist heritage center.