The Congreso neighborhood, west of Avenida 9 de Julio, is a perfect example of the two completely different sides of Buenos Aires, which somehow exist in harmony. During the day, the area is perfect for strolls, sightseeing and photo opportunities. The National Congress building is here in all its stately glory (check out the huge green dome planted on top), as well as other historic buildings, old cinemas and theaters. The grassy Plaza del Congreso and cafĂ©s on Avenida de Mayo are lovely places to sit and take in the vibrant city. There is a small flea market in the square near HipĂłlito Yrigoyen street. But once darkness falls, this part of town (like others in the city center) becomes deserted and a little seedy, with the plaza now the spot where homeless and the police, who keep an eye on them, congregate. Itâ€™s still pretty safe, but not an enjoyable place for late-night wanderings. If you want to catch sight of the gritty politics of BA, disgruntled protesters can often be found in the plaza.