4. Victoria Falls, Zimbabwe.

The Victoria Falls constitutes one of the most spectacular natural wonders of the world. The Local people call it "Mosi-oa-Tunya" means the smoke that thunders and the Falls are remarkable. There is a magic about them manifested in the towering column of spray when the river is high, the thunder of the falling water, the terrifying abyss and tranquil lagoons upstream in which hippo and deadly crocodiles lurk.

This legendary waterfall is among the biggest, and most awe-inspiring, on the planet. The Zambezi River is more than 1.25 miles (2 kilometers) wide when it cascades over the lip of a large basalt plateau and plunges as much as 354 feet (108 meters). The flow has been slicing slowly through this plateau for some two million years. During this time the river has slowly retreated and the remnants of earlier, ancient falls can be seen in the gorges downstream from the current cataract.

The national border between Zambia and Zimbabwe lies midstream, and national parks of both nations exist on either side of the Zambezi. The gorges and cliffs below the falls in these parks are prime territory for raptors, including falcons and black eagles.

Today several hundred thousand visitors from around the world trek to the falls each year; several hotels, restaurants, campgrounds, and other tourist businesses cater to them. The beauty of the falls lies in their natural state, but the area is at some risk of runaway tourism-based development—more resorts, hotels, and even a possible dam below the falls that could flood several park gorges. Operators in the area offer everything from helicopter overflights to bungee jumping, and the management of these activities while preserving a quality visitor experience for all is an ongoing challenge.

Remarkably preserved in its natural state, Victoria falls inspires visitors as much today as it did David Livingstone in the 1860's. The falls and the surrounding area have been declared National Parks and a World Heritage Site, thus preserving the area from excessive commercialisation. The Falls are spectacular throughout the year, but February onwards, after the rain season, has the heaviest flow and volume of spray.