What city in South America should I travel to?

I'm wondering which is the safest, and I'm in college so I'd like a city that's coastal and has nightlife.

Idk, but Cali Colombia or San Andres Colombia is BEAUTIFULL!!!!!!!!!!! Also Rio De Jainero! Go there i was at Cali in December and it was pure fun!♥

Go to Cartagena, Colombia. The walled city adds wonderful ambiance and the night life rules. San Andres is nice, but not a great night life IMHO. Cali is moderately dangerous for gringas.

Buenos Aires, Argentina! its an european city in latin america.

Montevideo, Uruguay.
If you get there, you should deff go to Punta del Este, or any other small cities, outside the capital, Piriapolis, Punta del Diablo, is beautiful, safe, and cheap.

here are some pics,
http://images.google.com/images?um=1&hl=en&q=punta+del+este

quito ecuador, ex-patrimonial culural city of latin america