The Romans

"The Romans" was Doctor Who's first 'comedy' serial. Instead of striving for realism, 'The Romans' features a comedic portrayal of the Emperor Nero, a strange subplot involving Nero's murder, and the first incident of the Doctor causing important historical events to take place, in this case the burning of Rome.

As usual, the TARDIS crew all blend in perfectly with the surroundings and newcomer Vicki is instantly likable. Before long, everybody is split up and no one knows where anyone else is. Before long, the Doctor gets involved in something 'over his head', and after just missing Barbara by the skin-of-his teeth on numerous occasions, we are introduced to something that has remained an important part of Doctor Who ever since this serial, dramatically altering history.

Ian and Barbara experience the opposite end of the Roman way of life as they become slaves. The people they meet are all interesting and the script has given them a lot of depth and background, adding to realism. 

As all the character's paths entwine, the story draws to a close, and the Doctor and Vicki return to the TARDIS completely unaware that Ian and Barbara have been in the same locations as them all along, except without them ever meeting.

"The Romans" shows that the programme can take on any format or genre it likes, and for that reason, this serial is a true classic.