The Gulf of Bothnia is the northernmost part of the Baltic Sea, situated between the west coast of Finland and the northern part of the east coast of Sweden (and Norrbotten – North Bothnia). The gulf is divided into the Gulf of Bothnia, the Kvarken (northern), and the Sea of ​​Bothnia. To the south of the gulf lies the island of Åland, situated between the Sea of ​​Åland and the Archipelago Sea.

Lake Peipus is the largest transboundary lake in Europe, located on the border between Estonia and Russia. In Estonia, the lake is near the city of Tartu and covers an area of ​​3,555 km². Its average depth is 7.1 meters, with a maximum depth of 15 meters. Lake Peipus consists of three parts: a northern section, a southern section, and a central section that acts as a bridge between the other two.

The Salish Sea is a marginal sea of ​​the Pacific Ocean located in the province of British Columbia in Canada and the state of Washington in the United States. It includes the Georgia Strait, the Juan de Fuca Strait, Puget Sound, and a complex network of adjacent canals and waterways.

Lagoa Mirim is a large estuarine lagoon stretching from the southern part of the Rio Grande do Sul state in Brazil to eastern Uruguay. It is separated from the Atlantic Ocean by a sandy isthmus and is partly barren.

The Paraná River is a river in south-central South America, flowing through Brazil, Paraguay, and Argentina for approximately 4,880 km (3,030 miles). Among South American rivers, it is second only to the Amazon in length. The Paraná merges with the Paraguay River and then further downstream merges with the Uruguay River to form the Río de la Plata, which empties into the Atlantic Ocean.

The Irtysh River is a river that flows through Russia, China, and Kazakhstan. It is the main tributary of the Ob River and also the longest river in the world. Notably, it is nearly 600 km (373 mi) longer than the Ob. Its average depth ranges from 6 to 15 meters (20-49 ft).

The Uruguay River is a major river in South America. It flows from north to south and forms part of the border between Brazil, Argentina, and Uruguay, separating several provinces of Mesopotamia in Argentina from the other two countries. Many people, animals, and plants depend on this river for survival, making it a vital waterway for both nature and humanity.

The Strait of Hormuz is a strait between the Persian Gulf and the Gulf of Oman. It provides the only sea passage from the Persian Gulf to the open ocean and is one of the world's most strategically important choke points.

The Rio Grande, known as the Río Bravo in Mexico, is one of North America's most significant rivers, extending approximately 1,900 miles (3,060 kilometers) from its source in the Rocky Mountains of Colorado to its mouth at the Gulf of Mexico. It serves as a vital water source for millions and forms a natural border between the United States and Mexico, particularly between Texas and several Mexican states including Chihuahua and Coahuila.

Mount Elgon is an extinct shield volcano on the border of Uganda and Kenya, north of Kisumu and west of Kitale. The mountain's highest point, named "Wagagai", is located entirely within Uganda. Mt Elgon was once Africa’s highest mountain, far exceeding Kilimanjaro’s current 5,895m. Millennia of erosion have reduced its height to 4,321m, relegating it to the 4th highest peak in East Africa and 8th on the continent.