For centuries, mariners have spun tales of gargantuan waves, 100-feet high or taller. Until recently scientists dis​missed these stories - waves that high would seem to violate the laws of physics. But in the past few decades, as a startling number of ships vanished and new evidence has emerged, oceanographers realized something scary was brewing in the planet’s waters. They found their proof in February 2000, when a British research vessel was trapped in a vortex of impossibly mammoth waves in the North Sea - including several that approached 100 feet.

Susan Casey is our premiere chronicler of the aquatic world. For The Underworld she traversed the globe, joining scientists and explorers on dives to the deepest places on the planet, interviewing the marine geologists, marine biologists, and oceanographers who are searching for knowledge in this vast unseen realm. She takes us on a fascinating journey through the history of deep-sea exploration, from the myths and legends of the ancient world to storied shipwrecks we can now reach on the bottom.

Since the dawn of recorded history, humans have felt a kinship with the sleek and beautiful dolphin, an animal whose playfulness, sociability, and intelligence seem like an aquatic mirror of mankind. In recent decades, we have learned that dolphins recognize themselves in reflections, count, grieve, adorn themselves, feel despondent, rescue one another (and humans), deduce, infer, seduce, form cliques, throw tantrums, and call themselves by name.

With its quaint villages, local restaurants serving up lobster rolls, and miles and miles of warm, sandy beaches, Cape Cod, Massachusetts, is famous for being America’s carefree seaside getaway. But in August 2012, the first confirmed shark attack in almost eighty years occurred in the region. As shark sightings quickly began to increase on Cape Cod and elsewhere and large beachside billboards warning about the growing shark population became a common sight, a boogie boarder died after being attacked by a great white shark in Cape Cod’s shallow waters.

Rising from the depths of the North Pacific lies a fabled island, now submerged just 15 feet below the surface of the ocean. Rumors and warnings about Cortes Bank abound, but among big wave surfers, this legendary rock is famous for one simple (and massive) reason: this is the home of the biggest rideable wave on the face of the earth.

Deep is a voyage from the ocean's surface to its darkest trenches, the most mysterious places on Earth. Fascinated by the sport of freediving - in which competitors descend to great depths on a single breath - James Nestor embeds with a gang of oceangoing extreme athletes and renegade researchers. He finds whales that communicate with other whales hundreds of miles away, sharks that swim in unerringly straight lines through pitch-black waters, and other strange phenomena.

We have a perennial fascination with sharks. Portrayed in the media and popular culture as killing machines, we are awed by their power and strength. But the shark is so much more—a marvel of the sea, they have evolved over 450 million years into more than 500 species, from the bioluminescent kitefin to the tiny dwarf lantern shark, the sociable lemon shark to the cow shark, which can birth up to 100 pups in one litter. Bringing balance to the ocean’s ecosystem, our planet is at serious risk when these amazing creatures are threatened.

On January 28, 1742, a ramshackle vessel of patched-together wood and cloth washed up on the coast of Brazil. Inside were thirty emaciated men, barely alive, and they had an extraordinary tale to tell. They were survivors of His Majesty’s Ship the Wager, a British vessel that had left England in 1740 on a secret mission during an imperial war with Spain. While the Wager had been chasing a Spanish treasure-filled galleon known as “the prize of all the oceans,” it had wrecked on a desolate island off the coast of Patagonia.

There are few remaining frontiers on our planet. But perhaps the wildest, and least understood, are the world's oceans: too big to police, and under no clear international authority, these immense regions of treacherous water play host to rampant criminality and exploitation.

438 Days is the miraculous account of the man who survived alone and adrift at sea longer than anyone in recorded history - as told to journalist Jonathan Franklin in dozens of exclusive interviews.

It's every parrothead's dream: to leave behind the rat race of the workaday world and start life all over again amidst the cool breezes, sun-drenched colors, and rum-laced drinks of a tropical paradise. It's the story of Norman Paperman, a New York City press agent who, facing the onset of middle age, runs away to a Caribbean island to reinvent himself as a hotel keeper. (Hilarity and disaster - of a sort peculiar to the tropics - ensue.)

Combining rich historical detail and a harrowing, pulse-pounding narrative, Close to Shore brilliantly re-creates the summer of 1916, when a rogue Great White shark attacked swimmers along the New Jersey shore, triggering mass hysteria and launching the most extensive shark hunt in history.

At 28,251 feet, the world's second-tallest mountain, K2 thrusts skyward out of the Karakoram Range of northern Pakistan. Climbers regard it as the ultimate achievement in mountaineering, with good reason. Four times as deadly as Everest, K2 has claimed the lives of seventy-seven climbers since 1954. In August 2008 eleven climbers died in a single thirty-six-hour period on K2–the worst single-event tragedy in the mountain's history and the second-worst in the long chronicle of mountaineering in the Himalaya and Karakoram ranges.

In 1991, acting on a tip from a local fisherman, two scuba divers discovered a sunken German U-boat, complete with its crew of 60 men, not too far off the New Jersey coast. The divers, realizing the momentousness of their discovery, began probing the mystery. Over the next six years, they became expert and well-traveled researchers, taught themselves German, hunted for clues in Germany, and constructed theories corrective of the history books, all in an effort to identify this sunken U-boat and its crew.

In this extraordinarily rare memoir by an active-duty jumper, Jason Ramos takes listeners into his exhilarating and dangerous world, explores smokejumping's remarkable history, and explains why their services are more essential than ever before.