Water covers nearly three-fourths of Earth’s surface, but most of it is salty or permanently frozen. Around 70 percent of the world’s fresh water is locked in the ice of Antarctica. Around 53,000 cubic miles of water passes through the planet's lakes and rivers, which are under constant assault from human encroachment. By the year 2025, 52 countries — two-thirds of the world's population — will likely experience water shortages, according to U.S. government data. Fortunately, there are several organizations around the planet dedicated to conserving our rivers and preserving our future. Here are 10 images of some of the world’s most majestic rivers, and some ways we can help them thrive. Pictured here is the Lama River, located near Moscow.

1 of 8 The Amazon Photo: Pedro Szekely/Wiki Commons The Amazon River, the basin of which covers a land area the size of the continental United States, is an amazingly biodiverse area. It is home to 60 percent of the world’s rain forests, and it plays an important role in regulating the climate of South America — and North America. It is believed to be about 4,000 miles long. Remoteness has protected it from human encroachment, but that situation is rapidly changing. As many as 60 dams are planned for Brazilian sections of the Amazon alone. These projects would displace indigenous people and flood national parks.

2 of 8 The Mississippi bluepoint951 /Flickr. The Mississippi, called “America’s Greatest River,” rises in western Minnesota and flows south for 2,530 miles into the Gulf of Mexico. But after more than a century of abuse by humans, the Mississippi (pictured here from Baton Rouge) is in dire need of help. Due to an abundance of locks, dams and 1,678 miles of levees, the river utilizes only 10 percent of its original flood plain. The Audubon Society says this means the river now supplies barely any of the sediment needed to support its delta. Consequently, as much as 19 square miles of delta land disappear each year. Recent blows such as the Gulf oil spill have only worsened the situation. Fortunately, the Mississippi River has an abundance of conservation projects and initiatives dedicated to its care.

3 of 8 The Danube Photo: Daniel Mihailescu/AFP/Getty Images The Danube River — pictured here at Romania's Danube Delta — begins in western Germany, flowing 1,770 miles onto the Black Sea. Among other countries, it passes through Austria, Hungary, Croatia, Serbia, Romania and Ukraine. It drains the territory of 19 countries, making it the “most international river in the world.” It features a richly diverse biological and ecosystem that has been rigorously abused by humans for the past 150 years. Due to dikes, dams and dredging, as much as 80 percent of the river’s wetlands have been destroyed. Organizations such as the World Wildlife Federation (WWF) are one of many working to restore and conserve the area.

4 of 8 The Mekong eutrophication&hypoxia; /Flickr. The Mekong River — pictured here in Thailand — is an integral part of Southeast Asia’s ecosystem. Called the Lancang River in China, it starts in China, moving 3,050 miles through Burma, Laos, Thailand, Cambodia and Vietnam. It supports the world’s second most diverse fisheries and provides more than 60 million people with food, water and transportation. China’s construction of a series of dams along the mouth of the Mekong is negatively impacting the ecosystems below it. Organizations such as the Save the Mekong Coalition are contesting these dams while working to preserve the ecological integrity of the river.

5 of 8 The Yangtze Photo: Fred Dufour/AFP/Getty Images The Yangtze River runs almost 4,000 miles through China, making it the longest river in the country and the third longest river in the world. Considered a tremendous source of hydroelectric power, the river also contains the world’s most “notorious” dam. Construction began in 1995 on the Three Gorges Dam, which has displaces more than 1.2 million people and flooded hundreds of mines, factories and waste dumps. This has created a mass of pollution and waste flooding down the river, causing a chain of landslides threatening China’s largest fishery. China officially acknowledged the problems in 2011.

6 of 8 The Nile Photo: Rod Waddington /Flickr The River Nile of Africa is the longest river in the world, measuring more than 4,000 miles. It flows through northeastern Africa, ending in Egypt and the Mediterranean Sea. Several large hydropowered dams are planned for the river in Uganda, Ethiopia and Sudan. The Nile Basin Initiative works to achieve a sustainable management of the river’s resources. Pictured here is the Nile River between Luxor and Qena in Egypt.

7 of 8 The Congo Julien Harneis /Flickr. The Congo River is one of the most plentiful rivers in the world. It is thought to discharge as much as 1.5 million cubic feet of water per second. While parts of the river are polluted from urban waste and soil erosion, much of the pollution of the river is caused by human travel. The river is considered Africa’s main navigational system. The Grand Inga Dam, the world’s largest hydropower plant, has been proposed for the river in the Democratic Republic of Congo, one of the most politically corrupt areas on Earth.