Gualeguaychu is a small city about 300km north of Buenos Aires in the province of Entre Rios. In the summer they host Argentina's biggest and most well-known Carnaval celebration. It's not as big as the samba parades in neighboring Brazil but I was very impressed with the quality of the costumes and production. These pictures are from last February. One advantage of a smaller parade is that you can get close. As you can see from the picture above, I was very close.
Another important difference is that the parade isn't just held the weekend before Lent but rather every weekend from January to March.