The Puerto Rico Trench is the deepest part of the Atlantic Ocean, reaching more than 27,000 feet beneath the water’s surface. Located just north of Puerto Rico and the Virgin Islands, the trench marks the boundary between two tectonic plates and separates the Atlantic Ocean from the Caribbean Sea. The deepest point of the trench is called the Milwaukee Depth, named for the USS Milwaukee, the naval cruiser that first measured it.

Legend has it that when former U.S. First Lady Eleanor Roosevelt first saw Iguazu Falls, she remarked, “My poor Niagara!” Whether or not she actually said it, it’s true that the waterfall system on the Argentina-Brazil border dwarfs Niagara Falls. With an incredible 275 individual cascades, it is the largest waterfall system in the world.

Located in the Great Rift Valley of East Africa, Lake Tanganyika stretches for more than 420 miles and divides four countries — Tanzania, the Democratic Republic of the Congo, Burundi, and Zambia. At 12,700 square miles in total size, Lake Tanganyika the second-largest freshwater lake in the world, after Russia’s Lake Baikal.

If you thought the Great Salt Lake was salty, then you’ve never floated in Gaet’ale Pond in Ethiopia. While the average percentage of salt by weight is 3.38% in the world’s oceans, this small body of water measures a whopping 43.3%. In contrast, the Great Salt Lake’s saline content varies from 5% to 27%, while the Dead Sea, another famously salty body of water, measures 34%.

The Pantanal region covers more than 70,000 square miles in three countries — Brazil, Bolivia, and Paraguay — and contains both national park land and areas protected as UNESCO World Heritage Sites. Saturated with torrential rains, the Patanal's enormous basin fills every year, draining slowly into the Paraguay River. The region has the highest concentration of wildlife in South America.

Also known as “Mosi-oa-Tunya” (meaning “The Smoke That Thunders”), Victoria Falls is the largest curtain of falling water in the world. It’s situated about midway through the course of the Zambezi River and marks the boundary between Zambia to the north and Zimbabwe to the south. The Zambezi River stretches for 1,599 miles, making it Africa’s fourth-longest river.

If you wanted to get to the bottom of Siberia’s Lake Baikal, you'd have to dive an astonishing 5,354 feet. In addition to being the deepest freshwater lake, it is also the planet’s oldest and biggest lake by volume, with as many as 1,800 endemic species of animals and plants that call it home.

Istanbul, Turkey, is divided by the Bosphorus Strait, which also connects two important seas — the Black Sea to the north and the Sea of Marmara to the south. The Sea of Marmara leads to the Mediterranean Sea via the Dardanelles Strait and the Aegean Sea, and because of this the Bosphorus has long been one of the world’s most strategically important maritime trade routes.

At more than 830,000 square miles, the Bay of Bengal in the northeastern Indian Ocean is larger than even the Gulf of Mexico. The Bay of Bengal measures roughly 1,000 miles wide, and it borders the countries of Sri Lanka, India, Bangladesh, and Burma. But while the Bay of Bengal is large, it's relatively shallow.

The Grand Prismatic Spring at Yellowstone National Park in Wyoming is a sight to behold, thanks to the literal prism of colors it emits. This powerful hot spring is deeper than a 10-story building and notable for the bright bands of orange, yellow, green, and blue that form around its edge.

Of the approximately 1.42 million lakes around the world, Canada is home to 62% of them. There are 879,800 lakes in Canada, according to a 2016 study published in Nature Communications. (The study only accounted for lakes greater than 0.1 square kilometers in size.) Russia is next with 201,200 lakes, followed by the U.S. with 102,500 lakes.

Located at the junction of Europe and Asia — touching Russia, Azerbaijan, Turkmenistan and Kazakhstan — the Caspian Sea has a surface area of 143,244 square miles. Despite its name, the Caspian Sea can be considered either a lake or a sea. While it has the size and salt content of a sea, it is entirely enclosed by land and embodies many of the characteristics of a lake.

Much less ominous than the Bermuda Triangle, the Coral Triangle is located in the western Pacific Ocean and includes the waters of Indonesia, Malaysia, the Philippines, Timor Leste, Papua New Guinea, and the Solomon Islands. The region is named for the huge numbers of coral that call it home, including nearly 600 species of reef-building corals, or 75% of the world’s coral species.

The Amazon is the world’s second-largest river, flowing through nine countries in South America. While there has been some historical speculation about its actual source, the most widely accepted theory is that the Amazon begins in the Andes of Peru. About two-thirds of the main river flows through Brazil, eventually emptying out into the Atlantic Ocean on Brazil’s northeastern coast.

Located in the Scottish Highlands, Loch Ness is the largest body of freshwater in Great Britain. The lake is most famous for the sea monster rumored to live within it, who is aptly named Nessie. Fishermen, locals, and visitors alike have reported their own Nessie sightings for years, which helps drive tourism to the area, as does Urquhart Castle along the lake's shore.

When Moses crossed the Red Sea, he was doing more than fulfilling a biblical prophecy. He was also crossing onto the Asian continent. The Red Sea sits in a fault depression that separates the enormous slice of Earth’s crust that is Asia from the African crust. In the northern end, it splits into two gulfs — the Gulf of Suez in the northeast and the Gulf of Aqaba in the northwest.

The Great Lakes account for 20% of all freshwater on the Earth’s surface. They include Lakes Superior, Michigan, Ontario, Erie, and Huron. Lake Powell, on the other hand, is a reservoir in Utah that was formed when the Glen Canyon Dam was completed in the early 1960s. It is the second-largest reservoir in the U.S..

Ranging in elevation from 1,300 to 1,400 feet below sea level, the Dead Sea is the lowest geographic point on Earth's landmasses. It also boasts many other unique geological features — for example, it’s one of the saltiest bodies of water on Earth and purportedly does wonders for bathers' skin.

Oceans cover 71% of the Earth’s surface, and the Pacific Ocean is by far the largest of the world’s ocean basins, containing almost twice as much water as the Atlantic Ocean. The Pacific Ocean could fit all of Earth’s continents. It spreads across 63 million square miles and contains more than half of the free water on the planet.

The Adriatic Sea, the northernmost arm of the Mediterranean Sea, is located between the Italian and Balkan Peninsulas. It stretches for about 500 miles and borders the country of Italy to the west, and Albania, Bosnia and Herzegovina, Croatia, Montenegro, and Slovenia to the east.

The "Chunnel," aka the Channel Tunnel, is a 31-mile underwater tunnel that connects England to France. Opened in 1994, the Chunnel cut travel time between England and France to a convenient 35 minutes by rail. The longest undersea tunnel in the world, it runs under the English Channel for 23 miles.