The Emilio Goeldi Museum was closed for renovations in August 2009 (the aquarium and snake section are closed too - renovations still ongoing as at January 2012), but the garden/zoo grounds are open.  It is a very pleasant, very well-shaded place to walk around for an hour or so, looking at the various plants and the small variety of animals, including an impressive-looking leopard, both large and small jacaré (caymans/alligators) and birds. All signs on the animal exhibits are in English too. Admission is only 2 Reais.  You can buy snacks and drinks on the grounds.