I've cashed in some United miles and taking the family to the bottom of Africa and top of Europe next July. I'm looking to get a hotel chain credit card to be used for some free stays in Cape Town, Johannesburg, Oslo and Stockholm. It would be preferred to have the same brand if at all possible.

I'm Hyatt Diamond in the States but not really options in those places for their properties. Have some Marriott and Hilton points already as well.

Any suggestions on a good card to maximize some awards stays would be appreciated.