Swaths of greenery, lakes and rivers separate playgrounds and skating rinks, art galleries and performance spaces in this derelict steel-factory complex turned urban park. Sesame Street characters have their own theme park, as do parrots and macaws. Industrial chimneys punctuate the rehabbed landscape, and one massive blast furnace is now Horno 3, a hands-on steel museum where you can ride the original (but refitted) ore elevator up the tower to take in city and mountain panoramas.