This is Rio's pre-eminent praça, officially the Praça XV do Novembre. Located next to the waterfront, it is here that the the Brazilian republic was proclaimed on November 15, 1889. Governors and royalty lived here and there is now a crafts market and the Feria de Antiguidades, where you'll find antiques (new and old), food and drink and a fun shopping experience.
In this area, the walking tour turns historical to see:
Igreja de São José
Palácio Pedro Ernesto - today headquarters of the Municipal Council
Palácio Tiradentes - named for the dentist turned national hero, Joaquim José da Silva Xavier
Paço Imperial, the Imperial Palace, now restored and cultural center
Chafariz do Mestre Valentim, the Pyramid Fountain
Panteão de Osório
Igreja de Nossa Senhora do Carmo da Antiga Sé
Igreja de Nossa Senhora da Ordem Terceira do Carmo
Arco do Teles and the Travessa do Comércio - colorful and historic shops, restaurants and churches
Igreja de Nossa Senhora da Lapa dos Mercadores
Igreja da Santa Cruz dos Militares
Centro Cultural Banco do Brasil hosts a changing variety of exhibitions. make sure you enter and look up at the dome
Casa França-Brasil also displays exhibitions of a temporaty nature
Igreja da Candelária
Igreja Nossa Senhora Mãe dos Homens
Igreja Nossa Senhora da Conceição e Boa Morte