Victoria Falls, Zambia/Zimbabwe
Victoria Falls in Africa is considered by some measures as the world's largest waterfall and is listed as one of the Seven Natural Wonders of the World. It sits on the border between Zambia and Zimbabwe and is remarkable for its mile-long width. It's fed by the Zambezi River and is a great place to visit in the spring. The rainy season ends in early April, and the following six weeks are when the river flow peaks and the falls are raging. The thundering spring waters can make viewing the falls from the ground difficult but greatly enhance the view from above — sightseeing helicopter tours can be had for as cheap as $120.