Sorry for the vagueness but I remember watching a series of sorts in class in school about 10-15 years ago. It involved some sort of quest to find a chest and/or key that when eventually unlocked opened a pathway to ancient Rome. It led into some sort of building where all the romans were walking around and I think an episode ended on one of them going into the portal. Any ideas?
Think it was an English series.
Is it possibly the "Box of Delights"? It was a British children's series based loosely on the book of the same name. It was rebroadcast in the USA in the 1980's as part of the "Wonderworks" series on PBS. The story concerned a magical box with vast powers that was being pursued by sinister-but-debonair werewolves. There were a number of separate adventures relating to the box, but one included the main character entering the box and ending up in Roman times.
The series had a wonderfully spooky atmosphere and has always been one of my favorites. It doesn't seem to be currently available for purchase, but you can find the entire thing on You Tube.
Think you are thinking of "The Legend of the Lost Keys", which was part of the Look and Read series. We used to watch it in primary school too.
EDIT: If my memory serves correct, the city Heritron in the series was in a parallel universe where Rome never fell - which would explain why the OP thought it was Rome. The entire series was styled in a "Roman" manner: with togas, and a Janus organisation, and a roman numeral riddle in the first episode (I think).
