My 2018 epic long magnum opus rock opera (37 new U.N. countries in 7 months) actually makes perfect logistical sense in my twisted mind.
My dream (which has been IT since I prioritized traveling as #1 almost 4 years ago) is to experience wild animals in Africa. By experience, I mean bush camping among wild animals, in all the African countries glorious for animals, for as long as I can physically manage. To reach Africa, I must connect through Europe, so I might as well add Europe on either side of Africa. See? 1+1=37
Seriously though, I often suggest travelers pair Europe and Africa together because Europe is also a supply store and rest area. Due to proximity, Europeans travel more to Africa than North Americans do, so Europe has more suitable travel things to buy. Due to proximity, Europe is a comfortable way to rest before entering Africa and recover after exiting Africa.