Not really going to tell you what it is because whichever way it's translated, it sounds horrible. But, if you are into meat and tenedor libre asado then you have got to try "Chinchulines". I promise you will not regret it. Also Morcheja. They are both delicious.
Basically it's a landfill just behind Puerto Madera (three blocks behind, going away from the city and towards the Rio de la Plata). It's been a landfill for many years now and giving various plants, trees and lots of different animals the chance to grow there. If you want to go for a quiet walk, away from the hussle and bustle of the city, this is the best place to go. It's got water and many different species of butterflies and plants, lizards and birds. It's probably the biggest green space I know of in Buenos Aires that you don't have to walk too far to get to.
Avenida Corrientes, follow the avenue down to Luna Park then on to Puerto Madera, and just keep walking - you can't miss it. There are two entrances at both ends each entrance is about 2km apart and then you can enter, absolutely free.
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