It's common knowledge that spending time surrounded by trees and plants can increase your energy levels. If walking around town has tired you out, Izvor Park is a perfect place to stop and recharge your batteries.
You'll have sightseeing choices galore in Bucharest City-Centre. Izvor Park is a good place to start here, but there are plenty of other worthwhile sights to check out. Palace of the Parliament, Romanian Athenaeum, and Cismigiu Garden are not far from the recreation and green space and will top off your day nicely.