Circus park is fairly large (26 ha) and very close to the city center, connected to one of the busiest boulevards in Bucharest, Soseaua Stefan cel Mare.
It was especially built in 1960 to complement the Globus Circus arena and it does that very well while still being an impressive park. It has artificial hills with downgrading elevation towards a small lake (with natural springs) in the middle. This acts as the centerpiece and during the summer it’s swamped with Egyptian lotuses and hundreds more species of flowers, trees and animals, making it also a great place for nature photography. People say it has a big “European pond turtle” population (how this happened is still a mystery) although I’ve never seen one.
I use the park for running and it’s great for that. It has 2 rings, a smaller one, flat, around the lake and a larger one, slopped, on the outskirts; it includes a small hill acting as a great vantage point. The only downside could be the not-so-great surface, it’s asphalt, but at least it’s not cement.
Walking around the park gives you great freedom as it has no symmetric alleys or features (this was on purpose to give it a feeling of the wild), it has a lot of intertwined paths and weirdly located benches.
This is my favourite park in Bucharest.