America the Beautiful

Hang-glider pilots launch themselves over Yosemite Valley during a wildfire, a marine biologist takes a memorable dive through a Channel Island kelp forest and an arborist scales to the very top of a towering redwood.

Highliners walk 400 feet above the floor of Mineral Canyon, a 73-year-old rancher fights to preserve her historic cattle ranch and descendants of an ancient civilization restore the ruins of an irreplaceable American artifact.

Wildlife filmmakers capture incredible footage of a grizzly and wolves competing for food in Yellowstone National Park, climber Conrad Anker does a late winter ice climb in Hyalite Canyon and a summer rock climb on Devils Tower.

Photographer Ian Ruhter attempts to capture iconic images of Monument Valley using a camera that he built from a truck. Using a process called wet plate collodion, Ruhter utilizes his truck as the actual camera to make the photos larger. With the truck, he is able to become the mechanics inside the camera. But as he attempts to take the perfect shot, Ruhter's meticulous process is interrupted by high winds. By the banks of the Salt River, Becky Standridge works to document and protect one of the last known herds of wild horses. Standridge brings her camera out daily for pictures of the majestic horses, getting to know their stories and habits. Standridge takes to the sky in an ultralight to see if she can spot any familiar beasts - and is elated to capture both old and new faces. In central Arizona, mountain biker Lars Romig is drawn to the red sandstone landscape of Oak Creek Canyon. As part of the Verde Valley Cyclists Coalition, Romig helps maintain mountain biking trails so he can continue to practice his craft. Romig and his friend weave through the sharp turns of the Hangover Trail before challenging themselves to run one of the steepest drops in the area: Sick Rock. The 300-foot near-vertical drop requires precision, control and mental preparation.

The Hudson River Gorge; a flight over Adirondack Park; cliffs in Shawagunk Mountains; New York City's Central Park.

Life-long residents of St. John, Jason Siska and Jane Conrad share the snorkeling secret of Hurricane Hole with a young local boy named Craig. As a tour guide, Jason's favorite place to take people snorkeling is Hurricane Hole. Craig has lived in St. John his whole life and, surprisingly, has never visited the remote location. Reaching the deserted part of the island, Jane, Jason, and Craig take a dive into the unique underwater environment that is unlike anywhere else in the world. The three snorkel around the undisturbed paradise that showcases colorful corals growing on the roots of mangrove trees and a variety of sea life. Craig is really excited to see a new part of the island and hopes to come back and introduce it to his friends. In Northwestern Puerto Rico, Rossano Boscarino battles one of the largest subterranean rivers in the world to explore new passageways inside an underground cave. Rossano is a tour guide and cave explorer, and today he is entering Angeles Cave with his crew to clear a log jam so he can take his tour through new areas. As they enter the dark cave, they walk through a big room with beautiful rock formations that leads them to the beginning of the underground river. Rossano explains that the most dangerous part of being in the cave is combating the river because of the unexpected flash floods. Branches and the fast water flow challenge them until they finally make their way to the log jam. He and his crew use ropes and other tools to move the heavy logs out of the way, successfully clearing out the jam and opening a new passage in the cave. On the island of Vieques, researcher Mark Martin studies the mystery behind one of the world's brightest bioluminescent bays. Mark is bringing his friend Brenda, who is also a researcher, to measure the brightness of the bay this year. This is important because around this time last year, the bay went completely dark and no one could explain why. It significantly affected tourism since the bay is the main draw of Vieques, so local scientists decided to start taking research more seriously. As night falls, Mark and Brenda head out in their boat and scour the bay for signs of bioluminescence. They instantly see fish darting around which is a really good sign, but they won't have complete confidence in the state of the bay until they measure the bioluminescence with an instrument called bathyphotometer. They place the instrument in the water, hoping for high numbers. The readings are measured right away and come out extremely high. Mark and Brenda are elated, reassured that the bay is shining as bright as ever and hopeful it continues like this.

Professional kayakers Rush Sturges and Evan Garcia return to familiar grounds as they take on the raging rapids along the Columbia River Gorge. Approaching the river, they instantly feel the freezing temperatures of the water. The fast-flowing river leads to a 30-foot waterfall. Evan explains that he is recovering from a serious rib injury; so, even though he is joining Rush, he doesn't know if he will want to risk dropping over the waterfall. They start to paddle down the river, battling the treacherous water and dodging logs and rock hazards in the way. Before reaching the 30-foot waterfall drop, they stop to discuss Evan's chances of hitting it. He decides to go for it with no hesitation. Rush and Evan run the falls successfully and reflect on their excitement of being able to have this incredible scenery in their backyard. On Mt. Hood, cave explorers Eddy Cartaya and Barb Williams enter a glacier cave to perform research. Approaching the entrance they notice the drastic difference in size from previous visits. Due to warming temperatures, the cave is rapidly melting and falling apart, there are multiple cracks in the ceiling and huge chunks of ice on the ground. Eddy and Barb work quickly to avoid witnessing a potential collapse. They measure the cave and gather useful data as the walls of ice melt around them. After collecting as much research as they can, they escape the cave unharmed. Outside, they look back and wonder how much longer it will be intact, hoping they can continue to study it but realizing it may disappear much sooner than expected. In Crater Lake National Park, Bill Anders helps Jennifer Gifford maintain the hiking trails along one of the most spectacular natural wonders in the world, Crater Lake. To preserve the serenity of the wilderness around the lake, they use an old school crosscut saw to clear a log in the hiking trail, so hikers can continue to enjoy the beauty of this landscape.

At Corkscrew Swamp Sanctuary, burn boss Mike Knight uses fire to preserve ancient habitats in the area, including the last remaining stands of old growth bald cypress. Before his entire team arrives, Mike scouts the location of where the fire will be started. He is joined by Evan, an intern who has a passion for restoring nature. Mike shows Evan around the site. He explains how these environments need fire to thrive and also warns him of some of the dangers of setting off a controlled burn. The rest of the crew arrives and they start lighting up sections of the sanctuary. Mike explains that, as much as they try to control the direction of the burn, nature ultimately decides. Sections of the fire start getting out of hand, and some of their equipment fails. However, the crew takes every precaution, making sure the operation runs smoothly. In the end, the burn is successful and Mike and Evan reflect on how important these processes are to preserving old ecosystems. On the Florida panhandle, underwater cave divers Brett and Matt swim over 2400 feet into the dark abyss to search for signs of a potential sinkhole that is degrading the precious Floridan aquifer. Brett and Matt are extremely experienced cave divers. Cave divers have discovered trash in a remote section of the cave, so today they are bringing a device called a radio locator to see if the trash is coming in through an aboveground sinkhole. They also bring Becky, who will be filming their journey. As they get ready to enter the cave they make sure all of their equipment and backup air tanks are working. Brett explains that they must take a redundant amount of equipment, since there is only one way in and out of the cave, and they don't want to get trapped. The divers scooter through the cave until they finally find the room with the trash. They battle the heavy flow as they attempt to place the radio locator in the proper position so that the team above the surface can follow its signal. By the time they get the locator in place, Brett is running out of gas in his air tank. He is able to replace his tank with an extra one as they successfully swim out of the cave. The signal from the radio locator leads the aboveground team directly to a sinkhole, confirming how the trash made its way to the bottom of the cave. In the end, Brett explains how precious and fragile the Floridan aquifer is and how we must continue to protect it. Off the coast of Tampa, maritime archaeologist Nicole Morris dives to an old Civil War shipwreck with Danny, a descendant of one of the sailors who died in the shipwreck. Danny has done intensive research on his family tree and found that he is the descendant of a crewman on the USS Narcissus, an old Civil War tugboat that sunk near Egmont Key. Nicole and Danny ride to the wreck's location as Nicole explains to Danny what parts of the ship they will be seeing. Danny is very excited when they arrive at the site and dive in, even though the visibility underwater is not perfect. Nicole lets Danny touch the boiler, a part of the ship his ancestor would have used, and then she takes him to the plaque that recognizes this wreck as a state archaeological preserve. Danny is very moved and thanks Nicole for taking him to witness this personal piece of history.