I think I remember that one about Portugal, including the Algarve. And the area in France near the Pyranees has always interested me ever since I read an old Ann Bridge novel that was set there during the time of the Spanish Civil War.
There used to be a Scandinavian tour I took in 2002 that had a pre-trip in St. Petersburg. After that, we went to Helsinki, Oslo, Bergen, Copenhagen and Stockholm. There was no post-trip. That was a wonderful trip! We had such a good time and saw so much. I don't know why they took it off, although there was an announcement about a Scandinavia tour a couple of years ago, but they canceled it for some reason. Lack of interest, they said, but people who had signed up for it were furious.
Malta was great also! That was an extended stay for about 10 days. There's so much to see there, and the excavations go on constantly. Our local guide was a trained archeologist who could tell us in depth about what we were seeing. It's an extension now of the Sicily tour, but then we had a few days in Sicily as an extension.
And then there's the greatly lamented discontinued Costa del Sol. It was two weeks in Torremolinos with an option for a third week, which we took. Plenty of time to see other cities in Andalucia without being rushed from place to place, and plenty of time to see other things on our own. That was my introduction to GCT in 1999. And I'd go back in a minute!