This might already be on your list, or you might have already done it. This massive reef is the largest of it's kind. Sadly, Coral Bleaching is affecting 93% of the reef. Go there while you can!
See Victoria Falls, Zimbabwe and Zambia
This waterfall is around two times larger than Niagra Falls. There a five falls in the falls, four of which are in Zimbabwe, and one is in Zambia. This amazing sight will give you bragging rights over your friends, than them seeing Niagra falls.