A literal “once-in-a-lifetime” experience implies the kind of adventure that not everyone can live to tell. The most extreme trips in the world all offer some physical risk, but plenty of incomparable rewards. And if you’ve only got one life to live, why not make it count?

Photo Credit: Kevin Costain

EdgeWalk - Toronto, Canada

A walk around the tallest tower in the world may very well be the urbanite’s idea of an extreme adventure. The recently-opened EdgeWalk experience allows people to take a 20-30 minute walk around the top of the pod at Toronto’s CN Tower. Strapped to a movable harness connected to the tower at 1,168 feet, you must be good physical condition and screened for drugs, explosives and alcohol before venturing out on the ledge.

Photo Credit: Airwolfhound

MiG 29 Flight - Moscow, Russia

Instead of watching an air show from the ground, head to Russia for a sky-high front seat. The MiG-29 "Fulcrum" fighter jet flight experience offers a personal ride with a pilot for high-altitude aerobatics at G-force speeds from 3G to 7G. You get to set the severity of the ride, but you’ll need a blood-pressure check, a special pressure suit and a helmet with an oxygen mask before taking off in one of the most advanced jet fighters in the Russian Air Force.

Photo Credit: DenAsuncioner

Snorkel Jellyfish Lake - Eil Malk Island, Palau

If it’s good enough for Survivor, it’s good enough for the adventure junkie in all of us. Snorkel in the world-famous Jellyfish Lake on this small island nation near the Philippines. Those allergic will definitely want to cover up but otherwise, a minor sting or two on the lips will be the worst of it. We think the risk is worth the reward to experience this unexplainable natural wonder, where millions of harmless jellyfish pulsate everyday from one end to the other of this saltwater lake surrounded by scenic woods.

Photo Credit: Kvitlauk

Chernobyl Disaster Tour - Prypiat, Ukraine

Visit one of eeriest modern-day ghost towns on a tour of Chernobyl, just two decades after the worst nuclear disaster in the history of mankind. Never mind that you aren’t allowed to eat or smoke in the open air and must acknowledge the possible health complications from radiation.Along with a view of the reactor and a stop near the Red Forest, a highlight will be seeing what’s left of Pripyat, a city frozen in time and a regional relic to the stolen lives of the incident.

Photo Credit: Matthew Dryden

Bike on Yungas Road - La Paz, Bolivia

The North Yungas Road in Bolivia is a mountain biker’s dream conquest and commonly known as the “World’s Most Dangerous Road” or “Road of Death.” The steep and bumpy ride starts high in the rarefied air of the Bolivian Andes at La Paz and plunges for 40 miles through lush, sub-tropical Yungas to the sleepy town of Coroico. Be careful because the road is extremely narrow, hugging the walls of the sheer valley below as it snakes beneath waterfalls and rocky overhangs.