Although it’s been a long time since I’ve been to Histria (the first time was in 1993, the last in 2011), the site itself is over 2500 years old so I don’t think it will have changed that much recently!
If you are even remotely interested in ancient history (Greek or Roman) then Histria is for you. Originally a Milesian settlement (founded in the 7th century BC), it traded with Athens and other ports around the Black Sea. Histria is therefore the first city in Romania.
Around 30 AD Histria became a Roman town and was permanently occupied until around 600 AD. An invasion in the 7th century AD almost entirely destroyed the fortress, and the Istrians dispersed. The city was abandoned and forgotten.
Excavations of the site started in the early 20th century and there is now a wonderful museum full of artefacts, including pottery and gravestones, from the site.
Visiting the site is best done by car (unless you can get an organised trip from your hotel or local tourist agent). This is because the site is quite a way from the main road. There are some facilities but not many, I’d advise taking your own food and drink. The site is inexpensive to visit and information for sightseeing can be found on their website.