Machu Picchu: a pre-Columbian Inca city situated on a mountain ridge in Peru. A symbol of the Inca Empire. It's often referred to as "The Lost City of the Incas". Nowadays Machu Picchu is one of the seven wonders of the world.
I've been to Niagara Falls more times than I can count, and it is ALWAYS simply incredible. I've stood by the falls for hours, until soaked by the spray. I've also been there when the smaller section (The American falls) was frozen.
Glacier Perito Moreno: A Glacier-cave located on the northern end of the glacier in the Los Glaciares National Park in southwest Santa Cruz province, Argentina. It is one of the most important tourist attractions in the Argentine Patagonia.
The Great Blue Hole is the most popular dive destination in Belize. This massive hole under the water is near the Lighthouse Reef and creates a perfect circle of deep blue water. The water is 407 feet deep. It's breathtaking. YES BELIZE !