Many marine species live in coral reefs like the Great Barrier Reef—the world’s largest coral reef system.

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Watery Wonders of the World

Dive into some of our planet’s most amazing water features!

March 1, 2019

By Judy Dick

Credit: Jill Heinerth

Extreme explorer Jill Heinerth has dived inside pitch-black underwater caves, deep springs, and massive marine sinkholes. Her path to these mysterious spots started years ago. Jill fell in love with water as a fifth-grader, and today, she’s one of the world’s top female divers.

“Exploring the planet’s waters seemed like a chance to go someplace that nobody had gone before,” she explains.

There’s a long list of unexplored water features for Jill to choose from. Almost three-quarters of Earth’s surface is covered with water. Humans have seen only a fraction of its depths.

Conquering Caves

Jill’s goal is to explore as much of Earth’s underwater world as possible. She’s already made more than 7,000 dives. Early in her career, Jill joined a team mapping the Wakulla Springs cave system in Florida. She swam more than 10,000 feet through the underwater caves—the longest cave dive ever made by a woman!

Extreme Expeditions

Every time Jill takes a deep dip, she is always on alert. Faulty equipment, rockslides in caves, and fearsome sea creatures all pose deadly dangers. Her most hair-raising adventure was in 2000, when she led an expedition to Antarctica.

“We dived inside the largest iceberg in recorded history,” says Jill. “It was the size of the island of Jamaica!”

Jill and her team became the first to find and explore ice caves inside an iceberg. But they narrowly escaped disaster. Minutes after they left the iceberg, it collapsed and shattered into millions of pieces of ice!

What’s next for the daring diver? “This spring, I have many adventures planned,” says Jill. “One of them will be exploring shipwrecks in the Great Lakes.”

Who knows what watery treasures she’ll discover!

Continue the Learning Journey

Take a tour of oceans around the world with the video "The World's Oceans" below. Using the maps shown in the video, draw a map that shows the locations of the world's continents and ocean. Which ocean would you like to visit the most? Why? Put a star on your map in the ocean that you would want to explore the most.

Look through the slideshow "Map It!" and see if you can answer the quiz questions correctly. Then choose a watery destination listed in the slideshow. Create a travel brochure for this location, including facts, drawings or pictures about the place.

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