The Itaipu Dam, Brazil

The Itaipu Dam and hydroelectric power plant, close to the Iguasssu Falls, is the largest development of its kind in operation in the world and represents the accomplishments of the both Brazil and the neighboring country of Paraguay. The dam shifts the course of the seventh largest river in the world, the Parana.

The dam was built because both countries, which had suffered major droughts, wanted to use water from the rivers more effectively for crops, cattle, factories and industries. The 18 turbines, or engines in the dam wall, are turned by the water to generate 75 billion kilowatts of electricity each year, with cables taking this electricity to supply 25 percent of the energy consumed in Brazil and 78 percent of the demand in Paraguay.

The power plant is a major tourist attraction in the Foz do Iguacu area, and has received millions of visitors from around the globe. Tours include a film about the construction, which took seven years and 30,000 people, and a bus trip around the dam to various points of interest. You'll do best to purchase tickets in advance at local hotels.