There are several reasons to visit Sao Jorge Castle. The massive green spaces inside it are one of them. The garden is home to Portugal's primary native species and houses trees like cork oak, olive, carob, strawberry, and umbrella pine.

Head to the Black Chamber in St George Castle to catch unbeatable views of Lisbon. The optical system of lenses and mirrors in the Black Chamber provides 360º views of the city in real time. You can see Lisbon's famous monuments, riverfront, and houses from the Black Chamber. The mirrors provide incredible detail; you can even see people walking their dogs and locals at their windows kilometers away from the Black Chamber.

From the Romans to the Visigoths and the Moors, Sao Jorge Castle served as the home of several dynasties throughout history. The castle still has several remnants of its past, with the permanent exhibition housing a collection of objects found in the archaeological area. The exhibits provide insight into various cultures and lifestyles that existed in Lisbon from the 7th century BC to the 18th century.

Sao Jorge Castle is also home to annex buildings like the former Royal Palace of the Alcáçova. The royal palace was destroyed in the earthquake of 1755, but its traces remain at the Sao Jorge Castle. The building now houses the Permanent Exhibition, cafés, and Casa do Leão Restaurant. The romantic garden and patio have unique architectural features that provide insight into the former majesty of the royal residence.

Sao Jorge Castle is one of the most famous archaeological sites in Lisbon. The ruins found in the castle hold evidence of three periods in Lisbon's history: the first known settlement from the 7th century BC, the second from the Moorish era residential area from the mid-11th century, and the third from the last palatine residence in the former alcáçova. This makes Sao Jorge Castle Lisbon's most impressive archaeological site.