Brasil - Carnival: What happens when your whole country has a party? You get Carnival!!! Rio de Janiero is one of the biggest places where Carnival happens. Beyond Rio, Bahia has probably the best in the country. Yes Trinidad boasts big, as does New Orleans, but Brasil is huge and the whole country has huge celebrations. The Sambadromo is where all the main floats pass by and I got to see them being prepared - they are extravagant! If you can't pay the high prices for the Sambadromo, you can head off to anywhere in Rio on any day (the metro system gives you a list) and head to a bloco where people dance, drink and follow after a mini float. Old women get wasted, some Brazilian beauty sambas, a pallbearer spins, the drummers beat, and the rest of the floats have a great time. One passed right by my hotel so I didn't even have to leave. There's nothing quite like Carnival and if you ever get a chance to see Eastern Parkway Festival, Miami Carnival, Trinidadian Carnival, Caribana, or Mardi Gras it is a parade that will stay with you for life.
Rio de Janiero - Beach Culture: The beaches are a huge part of Brasil. People look beautiful, the boardwalk designs from Portugal, partying all night on the beach (safe during Carnival), hocking for cheap goods and coconut water, and simply strolling for that picturesque hotel, beach, mountain view that is the epitome of postcards. You can always watch people come down from hangliding to land on the beach and yes blocos pass by the beach too. My personal favorite? Ipanema, but there are many to choose from.
Rio de Janeiro - Favelas and Santa Teresa: Right next to Santa Teresa is Lapa which holds the Escaleron Stairs that are famous in music videos. However, the true treasure is walking around Santa Teresa, where I encountered a bloco with a fellow Brazilian friend along with some mate (tea, love it!) and acai, and simply enjoyed the hilly landscape that had gorgeous views with quaint living. On the flip side are the favelas which were once notorious for being cesspools of crime. However, they are now much more touristy and built up to have modern infrastructures like the internet, schooling, and sports facilities. There are some truly intriguing aspects of the favelas from their organic cooking, riding around in motorcycles (opportunity number 4 missed), the stacked families (new floor for each new set of offspring), and the friendliness of the people and of course in Brasil, women (that's a private conversation).
Rio de Janiero - Landscape: I think one of the best features of Rio is its diverse landscape. I mean it is bay that has tunnels and roads dug through its mountains. At the same time, it has extensive beaches where hotels take up residence. Furthermore, it has a dense forest with tons of flora & fauna, a mountain that looks like a sugar loaf, and Cristo Redentor that watches over all. I found myself just staring out at the biodiversity of Rio several times.
Buenos Aires - Paris of South America: Buenos Aires is fun to hop around in. There is a large amount of diverse neighborhoods here from Camenito street with its colorful corrugated iron, San Telmo artisan shops, Palermo nightlife, Puerto Madero, shopping near the obelisk, and the busy exchange areas near Florida street. There's also some glorious landmarks like the Cemetery (with the fanciest graves you've ever seen), Grand Opera, Evita Museo, and Independence square.
Buenos Aires - Tango/Milonga: There are some cheap places to learn how to tango in Buenos Aires. Afterwards, you can even practice your dancing with different partners. It's a lot of fun and in a way like speed dating/dancing. I had a ton of fun and it harkened me back to the salsa days of college. Beyond that, you can also watch the pros get down while having a few beers. It's a pretty cool scene and encapsulates some of the Palermo nightlife.
Uruguay - Colonia: Uruguay is extremely close to Buenos Aires, but don't forget it's an hour ahead as I almost missed my boat back! Anyways, this was part 5 of missing my chance to ride a motorcycle, but I did ok with walking to the little Colonia town founded by the Portuguese (yes once again). There were cool little museums, a light house, good beer and meat plates, along with some nice little views of the Atlantic. It's a nice little stopover from Buenos Aires, but make sure you convert your pesos back to Argentinian money.