You can go to Venezuela, but I don't recommend it for only a day. You will need at least two or three days. Then you can go to Henri Pittier National Park (about 4 hours by car) or to Paria. (1 hour by plane from Caracas)
Both is quite safe.
To stay in Caracas is really not a good idea in my opinion. Not interesting & not safe.
Here you can find some pics of my two trips to Venezuela.
2006:
http://www.teresniak.de/index_venezuela_english.html
2008:
http://www.teresniak.de/index_venezu...8_english.html