Once, this place was a forest, now it's a very nice, quiet and green park - Kiseleff Park, in the central part of Bucharest and it was designed by the same landscape architect like Cismigiu Park.
Nearby there are 3 museums you should see: the Museum of Natural History, the Geological Museum and the Museum of Romanian Peasants.
More info about the park you can find here:
https://bucharest-travel.com/kiseleff-garden-in-bucharest/
https://timesofindia.indiatimes.com/travel/bucharest/kiseleff-park/ps50188529.cms
https://www.tripadvisor.com/Attraction_Review-g294458-d10484071-Reviews-Parcul_Kiseleff-Bucharest.html
Bring a pen and enjoy!