My theory is that the "red" cruises are those that have been scheduled from the start. They are full because they have the people who originally booked for 2024 + the people from the cancelled spring 2023 sailings (some of whom were previously booked on 2022/21/20 sailings). Since then, Celebrity has added a bunch of new sailings, which are not sold out
I live in Belgium and Bruges is beautiful, so I can recommend that. I can also tell you that Flam is stunning! Stavanger is more industrial, but there are lots of lovely places around there. I haven't been to any of the others
This is stressing me out. We are booked on the 28 March 2024 sailing on Millennium. It's my husband's bucket list trip, planned for his retirement and we got a super deal. I doubt we'd be able to get anything similar for the price we paid. European bookings seem to be treated far less favourably