Brazil and Argentina are great countries for travellers.
They are very different from one another and very diverse in themselves.
The answer on where to backpack would depend on several parameters:
- What do you like to do? Do you like trekking? Beaches? Culture? Nature?
- What time of year you plan to travel.
- How much time/money you have?
Here are just a few examples:
Brazil:
- Salvador and the surrounding area are great for getting to know the Afro-Brazilian culture - dance, music, religion, capoeira, etc.
- The north (recife, islands such as Morro di Sao Paula, and more) is incredible for beauutiful beaches.
- The Amazon or Pantanal are best for an adventure in the nature.
- Carnaval is of different nature in different cities.
Argentina:
- Patagonia and Tierra del Fuego - great natural parks, trekking, glaciers, wildlife.
- Buenos Aires - city fun.
- West - Bariloche - ski, chololate, and more.
Enjoy!