Wall walks and Tagus views
Start outside, while your legs are fresh and the light is still useful. The wall walks and Place-of-Arms give the classic sweep over Baixa, Alfama, and the Tagus, and they explain why this hill mattered long before it became a photo stop. Do this first if clouds, crowds, or closing times are moving in.
Torre de Ulisses camera obscura
The Torre de Ulisses hides one of the castle's most memorable surprises: a periscope installed in 1999 that projects a live 360-degree view of Lisbon. It feels wonderfully analog in a city of phone screens. Because access is guided, limited, and weather dependent, check sessions before you wander too far into the site.
Archaeological site and museum
The archaeological area is where the castle stops being a simple medieval landmark. It preserves traces from a 7th-century BC settlement, 11th- and 12th-century Islamic houses, and later palace remains tied to the 1755 earthquake. The museum in the old royal-palace area turns those layers into objects you can actually read, from Olisipo to Moorish Al-Ushbuna and beyond.
Royal palace ruins and Praça Nova
The partially ruined royal palace sits near the center of the monument, with references reaching back to 1264 and 1277. After Manuel I moved royal life downhill in 1505, the hill slowly changed role; after 1755, the earthquake made that change visible in stone. Continue toward Praça Nova for archaeology, pines, and the peacocks that now patrol the old power center with comic seriousness.