1. Gordon Wiltsie/National Geographic / Getty Images Cliff camping. 2. Flickr: josefstuefer Skywalking in the Alps.Photo by Josef Stuefer 3. Corey Rich / Getty Images Portaledge camping at Yosemite. 4. MICHAEL NICHOLS/National Geographic Stock Climbing Redwoods. 5. pics.deon.li Sitting on the Trolltunga rock in Norway. 6. Flickr: opplevoodda Jumping on the Trolltunga rock in Norway.Photo by Opple Voodda. 7. Solent News/Rex/Rex USA British climber John Roberts in South Africa. 8. Keith Ladzinski/Barcroft Media /Landov Ice climbing a frozen waterfall. 9. buzzhunt.co.uk Extreme picnicking. 10. On the Kjeragbolten boulder in Norway.Photos via Nilsenbilder and Simon Taylor 11. 33m.lista.cl Extreme skiing at Grand Targhee, Wyoming. 12. cmhsummer.com Skywalking on Mount Nimbus in Canada. Photo by CMH Summer Adventures. 13. travelettes.net Tree camping in Germany. 14. amazon.com Vintage climbing photo taken from Gaston Rébuffat's book. 15. Desre Tate/Barcroft Media /Landov Extreme kayaking at Victoria Falls. 16. Handout / Getty Images Blake Aldridge dives 29 meters from the rock monolith during the Red Bull Cliff Diving World Series in Portugal. 17. Flickr: 29585346@N07 Climbing Mt. Wellington.Photo by S. Karpiniec/Creative Commons. 18. edgewalkcntower.ca On the Edgewalk in Toronto. (Courtesy of CN Tower.) 19. SINDRE LUNDVOLD / BARCROFT MEDIA A death-defying act by Eskil Rønningsbakken in Norway. 20. ec-general.blogspot.com How mountain climbers sleep. 21. reddit.com Alex Honnold at Yosemite.Shot taken from a documentary entitled Alone on the Wall about Honnold's adventures. 22. Flickr: copaintok74 Now imagine if you dropped your phone down there.Photo by Copaintok74/Creative Commons. 23. JIMMY CHIN AND LYNSEY DYER / NAT GEO STOCK / CATERS Base jumping in Yosemite. 24. JEFF CURTES / CATERS NEWS Glacierboarding. 25. SHAMS /BARCROFT MEDIA/Barcroft Media /Landov Trapeze paragliding. 26. Flickr: toon_ee Hanging out at the Sky Walk in Macau.Photo by toon_ee 27. Jared Alden / Getty Images 28. A ride at the Stratosphere Tower in Las Vegas. 29. dancersamongus.com In Ft. Tryon park.By Jordan Matters, from the book Dancers Among Us. 30. dinnerinthesky.com Dinner in the sky in Brussels. 31. hansrey.com Bike trail on the Cliffs of Moher, via Hans Rey. 32. 2001 LimeWave - Anki Knutsson & Lars Andersson Driving down a sand dune in Lucky Bay, Australia.