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 Mozambique Channel is an arm of the Indian Ocean located between the Southeast African countries of Madagascar and Mozambique. The channel is about 1,700 km (900 nmi; 1,100 mi) long and 419 km (226 nmi; 260 mi) across at its narrowest point, and reaches a depth of 3,292 m (10,801 ft) about 230 km (124 nmi; 143 mi) off the coast of Mozambique.

Located between Alaska and Russia, the Bering Strait is the only marine gateway between the icy Arctic and the Pacific Ocean. At its narrowest point, the strait is only 55 miles wide. The Bering Strait may be narrow, but it’s teeming with wildlife—beluga whales, bowhead whales, gray whales, walruses, polar bears, ringed and ribbon seals.

The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean in the south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east.

The Atlantic Ocean is the second-largest ocean in the world, covering approximately 106.5 million square kilometers (41.1 million square miles). It separates the continents of Europe and Africa to the east from North and South America to the west. The deepest point in the Atlantic Ocean is the Milwaukee Deep in the Puerto Rico Trench, which reaches a depth of about 8,376 meters (27,480 feet).

The Indian Ocean is the third-largest of the world's five oceanic divisions, covering 70,560,000 km2 (27,240,000 sq mi) or approx. 20% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by the Southern Ocean, or Antarctica

The Luzon Strait is the strait between Taiwan and Luzon, the northern portion of the Philippine archipelago. The strait thereby connects the Philippine Sea to the South China Sea in the western Pacific Ocean. This body of water is an important strait for shipping and communications. Many ships from the Americas use this route to go to important East Asian ports.

Lying between mainland China and the Korean peninsula, the Yellow Sea is one of the world's largest areas of continental shelf covered in shallow water, providing for rich fishing grounds and an important site for migratory birds. But decades of pollution is turning the sea to a colour other than yellow.

The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from sub-atomic particles to entire galactic filaments.

The Caspian Sea is the world's largest inland body of water, bordered by five countries: Russia, Kazakhstan, Turkmenistan, Iran, and Azerbaijan. Despite its name, the Caspian Sea is technically a lake, although it's often referred to as a sea due to its size and saline water. It spans an area of about 371,000 square kilometers (143,000 square miles) and has a maximum depth of over 1,000 meters (3,300 feet).