Volcanoes
Volcano Hazard Program
Global Volcanism Program

Castles of the World
Neuschwanstein Castle

Waterfalls

Protected Areas / National Parks

Roller Coasters
Amusement Parks
Roller Coaster Database
Thrill Coaster Tours
Coaster Buzz
Theme Parks
Water Parks

Single-Pipe Alpine Coaster in Mieders, Austria
300 Foot Long Slide in Japan

Some things to scratch of your Bucket List, preferably before you die.

Adventure Travel
Guided Tours: Hiking Tours, Climbing Tours, Biking Tours, Walking Tours, Driving Tours, Site Seeing Tours, City and Restaurant Tours, National Park Tours, Safari & Jungle Tours.
Boating: Whitewater Rafting, River Boating, Cannel Boating Tours, Canoeing, Kayaking, Expedition Cruises, Island Cruises, Ocean Cruises & Sailing. Photographic Tours, Wineries or Brewery Tours, Cave Tours, Bird Watching, Fishing, Hunting Tours, History Tours, Educational and Architecture Tours, Agriculture Tours, Sports Tours, Art Tours, Ecology Tours, Train Tours, Storm Chasing Tours. Float the Grand Canyon, Hike the Appalachian Trail, Cycle through Provence, Trek through Bhutan, Surf in Panama, Ski the Andes, Climb Half Dome, Ride horseback through Mongolia, Bike and hike in the Canadian Rockies, Safari in Tanzania, Dive the Great Barrier Reef, Sail in Antarctica, Machu Picchu, Mountain bike in the Rockies, camel trek in Morocco. A lot of Self-Guided Tours too.

Adventure Schools & Courses
Learn to Scuba Dive, Sailing Courses, Kayaking Courses, Climbing Courses, Wilderness and Survival Courses, Adventure Camps, Leadership and Teamwork Courses, Boot Camps, Space Camps, Hang Gliding, Skiing, Racing Schools, Sport Camps, Training Courses in Self-Defense, Fire Arms Training, Art & Cooking Courses to name just a few.

Adventure Racing
Multi Sport Competitions, Triathlons, Marathons, Bike Races, Road Races, Mountain Bike Races to name just a few.

Adventure Jobs
Resort Jobs, National Park Jobs, Cruise Line jobs, Summer Camp Jobs, Counselors, Guides, Instructors & Forestry to name just a few.

Volunteering Vacations
Volunteering in the US and around the world: Provide Health Care, Help Delivering Food, Building Homes, Training People, Teaching, Mentoring, Big Brother & Big Sister to name just a few.