Nestled by the riverside, Costanera Sur Ecological Reserve is the first of its kind when it was formed in Buenos Aires. A former dump-site, this park is a reprieve for sore eyes. Situated close to the downtown area, this nature reserve will take you away from bustling city life into a tranquil environment where nature will soothe you. Spread across 350 hectares (865 acres), this reserve is a popular haunt among birders, nature lovers, hikers, walkers and families. Hike, stroll or bike through the numerous trails crisscrossing lakes, trees and marshy lands to the river. There are picnic spots and benches as well in this park. You will find more than 300 types of birds. River turtles and iguanas are a natural sight at this place. Besides the three lakes, it also comprises of a couple of ponds.