TMNT (1987) Season 7, Part 1 (the European Vacation episodes): Review at AIPT!
The Turtles visit Paris, France (twice)! Lisbon, Portugal! The Austrian Alps! Venice, Florence and Rome (among other parts of Italy)! And Vatican City where they don't meet the Pope, unfortunately.
These episodes are a confounding hodgepodge of good and bad, with a lot of bewildering editing, but they're definitely entertaining.
In fact, "Artless" is one of the best episodes of the series! Also, the only episode of TMNT to include a picture of Jesus in it. At least that I know of.
Super weird.