Which ancient Roman buildings did Andrea Palladio study and measure in Rome?

During his visits to Rome, Andrea Palladio dedicated significant time to studying and measuring ancient Roman antiquities to inform his architectural designs.1

Specifically, he is noted for measuring the following:

• Ancient Roman baths: These structures were a primary focus of his archaeological study.1
• Ancient Roman temples: Palladio studied these buildings extensively, using them as the basis for his own work, including his reconstruction of the Pantheon for his treatise, I quattro libri dell’architettura.1

In addition to his direct measurements of ruins, Palladio collaborated with the scholar Daniele Barbaro to reconstruct various Roman buildings for an edition of Vitruvius’s De architectura. His research into these ancient structures allowed him to incorporate classical details and proportions into his own projects, moving beyond the contemporary Mannerist style toward a more ordered, classical approach.1