Fantasilandia - Santiago, Chile
Santiago is Chile's capital, and one of the biggest cities in South America. It's architecture is a mix of new office buildings with some old colonial houses. There's a hop on, hop off bus that goes arount the whole city and it works pretty much the same way the other hop on/offs buses around the world do. The subway system ir really good, it takes you everywhere and it's easy to understand how the lines are combined.
Fantasilandia is one of South America's biggest and most important parks. And is one of my favourites around here. It is located inside Parque O'Higgins, a local city park, and it's easily accessible by subway. The park even offers a shuttle from the subway station to the park gate, even though it's a 500m walk.
The park area is not big, but they make the best out of it. Their flat ride collection is very good, and includes a Condor, Top Spin, Disk'o, Go Karts, Drop Tower, Wave Swinger, Tidal Wave, etc. They also have 5 roller coasters: A SLC, a Wild Mouse, A Boomerang, A dragon and a Galaxi.
Their website is also very good and easy to navigate, even for non-spanish speakers. http://www.fantasilandia.cl/
The entrance fee is very cheap, around US$16.00!