• Tagged Acadia, Acadia National Park, architecture, bridge, Cadillac Mountain, carriage, environment, forests, islands, kayaking, Maine, Mount Desert Island, mountains, National Park, nature, ocean, places, Thunder Hole, travel, wetland, wildlife, woods

Acadia National Park along the rugged coastline of Maine may not be the first place that jumps to mind when thinking about America’s busiest parks, but maybe it should come to mind in the top 10 because it was the 9th most visited U.S. national park in 2011 with over 2,300,000 visitors. Acadia and Cuyahoga switched places from 2010, when Cuyahoga Valley National Park was ranked 9th in visitors. Acadia National Park protects more than 47,000 acres of lakes, ponds, woodlands, granite-domed mountains, and ocean shoreline along the coast of Maine. There are more than 140 miles of hiking trails, 45 miles of historic carriage roads, and scenic park roads for drivers. Diverse wildlife, waterfalls, cliffs, stone bridges and scenic vistas can all be found on this cluster of islands that make up Acadia. Hikers, bikers, horseback riders, kayakers, climbers, bird watchers and photographers are among the nature lovers who visit Acadia National Park. [40 Photos]

• Tagged adventure, Beaver Marsh, biking, Blue Hen Falls, Brandywine Falls, cave, Cuyahoga Valley, Cuyahoga Valley National Park, hiking, ledges, National Park, nature, Ohio, places, Ritchie Ledges, rock formations, train, travel, waterfall, waterfalls, wildlife

Coming in as the 10th most visited national park in 2011 is Cuyahoga Valley National Park in northern Ohio. It offers adventurers a little bit of everything in the 20,339 acres of woods, water, wildlife and even caves. There are nearly 200 miles of trails within the park for visitors to hike, bike or for horseback riding. The Cuyahoga River, meaning ‘crooked river’ in Mohawk, is fed by more than 190 miles of other waterways to tempt fishermen of all ages. Millions of years ago, water etched out the 105-foot high sandstone Ritchie Ledges and Ice Box Cave, also carving other wonderful rock formations. More than 2 million visitors came to Cuyahoga Valley National Park last year to enjoy the wooded ravines, gentle rolling hills, 170 waterfalls, historic railway, buildings and paths. Welcome to Ohio’s only national park, welcome to Cuyahoga Valley National Park! [40 Photos]

• Tagged animals, China, endangered species, giant panda cubs, giant pandas, nature, panda, panda cubs, pandas, places, Sichuan Giant Panda Sanctuaries, UNESCO World Heritage, UNESCO World Heritage Site, Wolong National Nature Reserve

Giant pandas are a highly endangered species, but an UNESCO World Heritage Site in China holds more 30% of the world’s panda population. These beautiful black and white bears roam on more than 2 million acres of the Sichuan Giant Panda Sanctuaries. It is the largest remaining contiguous habitat of the giant panda and contains the most important captive breeding site. The Chinese sanctuaries include seven nature reserves and nine scenic parks in the Qionglai and Jiajin Mountains. The Wolong National Nature Reserve alone has more than 150 of this iconic bears. [42 Photos]

• Tagged adrenaline junkies, adrenaline rush, canoe, extreme kayaking, extreme sports, Great Falls National Park, kayak, kayakers, kayaking, Oregon, rivers, waterfall, whitewater, whitewater kayaking, whitewater river rapids

There are many types of kayaking which can include paddling down gently moving water, but these kayakers are into demanding, dangerous whitewater. If trapping your legs into the cockpit and kayaking over insanely treacherous whitewater river rapids is not enough of an extreme adventure sport, then how about going over a waterfall in a kayak? Professional kayakers drop hundreds of feet going over falls. Extreme sports photographers captured these whitewater kayakers river running, rolling, creeking, playboating and during other extreme kayaking. We’re not quite sure if these kayakers are on drugs . . . or need to be. Or maybe all these adrenaline junkies need is the natural drug, an adrenaline rush? [45 Photos & 5 Videos]