...the oldest example of the promenade architecturale [formula] I have found thus far is the Pantheon in Rome itself. It is a very compacted version of the forest, hell, purgatory (inside/outside), and paradise.
A good portion of the architectural promenade formula can also be found in the entry sequence of Schinkel's Altes Museum. The facade/colonnade is the forest, and again the pilotis holding up the box. The dark portal under the stairs is the journey into hell. The ascension of the stairs is the inside/outside experience of purgatory, the middle level. And the museum's central pantheon is paradise, heaven, and the solarium. This interpretation of the Altes Museum, furthermore, sheds new light on Stirling's Düsseldorf and Stuttgart museums.