The Centro is where São Paulo began and where it stayed for three hundred years before the rich moved west to Paulista and beyond. The colonial-era buildings are mostly gone — the Pátio do Colégio is a 1979 reconstruction of the original mission — but the early-20th-century coffee-boom architecture remains, and there is more good early modern building per square kilometre here than anywhere else in Brazil. The Theatro Municipal, the Edifício Martinelli, the Edifício Banespa (now Farol Santander), the Mercadão, and Niemeyer's Copan are all within twenty minutes' walk of each other.
The Centro had a difficult late 20th century — middle-class flight, growing homelessness, the Cracolândia (crack-cocaine open scene) on the north edge — and it can still feel rough in patches. Visit during the day, stay alert in the evening, and do not flash valuables. The pedestrian streets around the Praça da Sé and the Mercadão are fine for daylight wandering, and the early-evening trade is back at the cultural centres (the Banco do Brasil CCBB, the Caixa Cultural).