Romania - 1 Free Day, what should I do?

I would stick largely to the old town (Lipscani) of Bucharest and the Palace of the Parliament. Take extreme care in Bucharest, I personally know a few people who have been mugged there, and beware taxis too, but the old town is safe for tourists and very beautiful. I haven't been but the National Museum gets high marks. We had a great, upscale (for Romania) dinner at the famous Caru cu Bere.

It's too difficult getting in/out of Bucharest by train to go anywhere worthwhile like Brasov for just one day, unfortunately.

Thanks, Sarah! I appreciate the guidance and caution flag