Originally Posted by
Carioca
If you get a chance, try running at Lagoa. Probably one of the most scenic runs will you ever seen. Afterwards try a cold coconut water to cool off and good luck!
Definitely second this recommendation. There is a nice bike/pedestrian trail encircling the Lagoon that is worth it. I wouldn't advise running there at night - not because of the safety, but due to the massive amounts of pedestrians going to the bars and restaurants around there.