The Australia/NZ cruise was on Celebrity and started in Sydney, then went to Melbourne, Tasmania and up the southern coast of New Zealand, ending in Auckland. It was like a 13-day cruise with 3 or 4 sea says, but it takes a while to get from place to place. I loved Tarrunga and Bay of Islands. We spent a sea day cruising the sounds (fjords) on the northern side of NZ. Great cruise. We few in early (New Years day) to go to Brisbane and see the Gold Coast. I could live there. We joined a group of LDS singles and watched Star Wars episode 7 at a drive in on bean bag chairs.
I did the Northern Europe cruise about 2 years ago. We left out of South Hampton (we took a bus from London) and it went to Oslo, Copenhagen and Hamburg. There are longer ones that go into St Petersburg, etc and I'd probably do that one, but I go where the singles groups go. We went to Ilse of Wight for a day trip after the cruise.
I would highly recommend either of the Asia cruises that I've done: In Jan, we did Singapore, Phuket (2 days), and 3 ports in Malaysia including Kuala Lumpur. And about 6 years ago, we did Singapore, a Thailand island where we rode elephants, overnight in Bangkok, a Cambodian island, 3 stops in Viet Nam and ended in Hong Kong. I believe it was an 11-day cruise. It was all beautiful, especially Viet Nam.